1. Proper base building will probably come in a later update, but it is likely to be the kind where you haul components from Kerbin. RTS style base construction on other planets would be for DLC at best, I would think, because it takes the game a long way from its present focus. 2. Not possible due to the 2.5km physics limit. Even if you had something strong enough to support its own weight over hundreds of km, the game would need a new sort of 'on rails' modelling for objects connected to the elevator cable that were further than 2.5km from your current position. Also space elevators, once built, rather trivialise the business of getting into orbit and that's a very big part of the game, so I think it is unlikely to be added. 3. This probably won't be added as stock either, for many of the same reasons. A modded one might well be possible though. 4. Definitely not with the current engine. The scale of even the smallest planetary ring would be far FAR beyond the current physics and part-count limits of the game. 5. I can however imagine a day when Squad might add a stock, hard-code ringworld, possibly with optional base construction facilities. Since nothing has ever been hinted at in this regard, it wouldn't happen for a long time yet though. 6. The current engine doesn't support terraforming and the scale of the game isn't really compatible with what you want to do. Even with Minecraft ease of mining it would take a ridiculous amount of time to shape an asteroid. Flying one is completely impractical. See the Scott Manley video where he talks about this. 7. This will almost certainly be possible as soon as resource mining is implemented. Version 0.21? 8. This could very well be part of a dedicated base building update but it isn't possible right now and nothing has been announced. You could probably build an unpressurised dome from stock parts now though. And since kerbals don't take their helmets off even on Kerbin, and never run out of air, who's going to know?