Okay, so I am just gonna post here any ideas I get that y'all may enjoy.
#1: Small weapons. AKA Hand lasers, small things that look like 16-bit laser pointers. You can change the setting from stun to full damage, but it cannot break blocks. It can only stun/damage players and mobs.
#2: Block Breaker: A massive handheld turret-like mining laser. Similar to the one from buildcraft(or was it IC2?), it requires a battery, and can break any block short of bedrock. It has a few options, such as firing type and power level. 1 is to just simply break blocks. It does not damage players or mobs at 49 or lower in power level. 2 is the wall fire, which fires a solid beam. At power level 100, it is 3x3, and it destroys blocks at 1 layer per 2 seconds. Each 10% down increases time and block radius. 3 is Macerator ray, which powders/burns/cooks whatever block it is used on, except obsidian and bedrock. 4 is destroyer, which destroys blocks in a random aoe of sorts. It has a range of 5 blocks ahead, and it does not make blocks into drops. It acts a little like creative mode block breaking, and is nasty for spaceship raiding.
#3: Crystals: An ore that comes in a variety that I will let you guys decide on. When mined, produces 2-5 crystals, which can have an effect similar to a battery if charged, and can make a fine blade, with the durability of iron and the power of stone. When you charge the crystals and make them into tools, they last as long as diamond, and have the strength of iron. When the crystals are charged, they can also be crafted into lanterns. When macerated, they become crystal dust, which can also be charged. The dust can be scattered and can do what redstone does, except it can carry a charge up to 20 blocks away. The charged crystal can either be "equippped" for basic boosts of strength, speed, and jumping (Like this: Charged crystal equipped to helmet=longer reach by 3 blocks, equipped to chest=strength boost equal to 2 hearts more damage and faster breaking, equipped to legs=speed boost like the potion, equipped to feet=higher jumping by 2 blocks and a resistance to falls). It can be combined with armor to make charged armor, upgrading the armor's durability and protection some. This only works for iron and above. Oh, and it will slowly loose charge and fall off of you if equipped.
#4: Land travel: A train of sorts made of iron blocks and an engine that can move on set tracks at a very fast pace. Also, vehicles that can hover above the ground by about 5 blocks or 3. Maybe both can be hooked up with heavy weapons turrets.
#5: Portable Fission Reactor: A small pack that, when you insert any form of matter into it, can produce a massive amount of energy. Take a normal fission reactor, and make it miniature, out of diamond.
This battery pack can be used to fuel small machines (small meaning anything that is not larger then 5x5 blocks), and is excellent for guns, mining, excavation, and farming equipment. This is also a good place to start for smaller power, other then combustion engines.
#6: Crystal/Mineral farms: Have you ever seen those really cool crystal growing kits? You know, the ones with those packets of powder you dissolve in water, which you drop a rock or two into? Something like that, except much cooler.
Ex: For the special crystals I mentioned well above in #3, the crystals are formed in caves with water in them. MOVING water. The water carries the necessary particulates of molecules that string together on crystals. A whole set of blocks could be made to produce crystals and other crystalline minerals.
I am imagining a circular tank (glass windows set in a 7x7 square tower, that goes up anywhere from 2-20+ blocks high), with a stone (baked cobble, silly) pillar in the middle. Fill the areas inside with water, and set an agitator (made from a machine block of some sort), which moves the water in a circle around the stone, and an enricher, which infuses the necessary particles into the water, beside the glass.
The Agitator would only be able to agitate one block layer at a time, so multiples would be needed for just one crystal generator, let alone a massive crystal generator. The Enricher can successfully enrich two block layers of this contraption, so you only need one for a crystal farm. But you will need multiples for a massive crystal farm.
Underneath the farm, you would want a collecting machine of some kind, since the agitator will make the water fast enough to break of longer piecess of crystal. These pieces will sink to the bottom, so the collector can collect (long cat is long statement)all of the crystals.
#7: Miniature machines & other things: Nanotech, Microtech, Minitech, and foot-below-tech. Nanotech cannot be seen by a normal microscope, and is very fine at making detailed work and electronics.
Microtech is better with biological engineering, and cellular rewiriing.
Minitech is insect-sized machinery used mainly for spying.
Foot-below-tech is for mobile working, such as carrying supplies, mining ores, gathering natural supplies, and general duties.
Now, here is the REAL idea: Biotech engineering, genetic manipulation (of sorts...minecrafted so that dna is a square), micro and nano processors, and helpers.
Bioengineering and such is something I have a few ideas on, but it would probably be a pain in the arse for programming. But, players start small, making something that reproduces fast, like a fleshy plant. Then they splice in something for faster regeneration, and then they can add some genes that allow strength/durability. The fleshy plants can be grown, over time and with a frame, into a ship frame that can produce its own atmosphere on the inside, as long as it has nutrients. Maybe it can be given an iron scale skin.
That is the fun idea.
#8: Stackable weaponry: These weapons are small mini-missile firing mechanisms. Make one, deals 3 damage to a person/armor of a ship. Stack them up, deals more. Ex: 100 stackables strapped together=300 damage.
Recipe? for the launcher:
IronNothingIron
IronGunpowderIron
IronIronblockIron
Missiles:
nothingIronnothing
irongunpowderiron
ironironiron
#9: EDIT!: NPCs should tell you stuff, like how much damage your ship is taking, how much energy it has at that moment, and so on. Basically living computer screens.
#10: Chemistry: There should be processes to produce different chemicals, such as Nitrogen, or Carbon. These chemicals can be used for various real world like things. Which I know very little about. :B
All I got so far. Will add more later. Thoughts?