I have the 2nd Edition version and enjoy playing with it. My group who I play 2nd Edition with tend to only use it say 1/5 games, with some mixed opinions. When we play we tend to stick to the Timescape characters, as they seemed rather overpowered compared to other characters. The objects are great to pick up but can really help one player run away with the game early on; but I guess that is the risk of plunging into the Timescape board!
The Timescape homebrew has highly interested me and is the top of the 'to print' list (just got to wait until I am back at work/uni) to print things out!) : I think it looks absolutley great on the pc and hope it looks as good when printed! Once I have played with it I will give a review of what I think of it.
As for an official expansion, well if it ever got made I would have to buy it wouldn't I!!!