
I enjoy creating too - my only beef here is with the slow parts. I think having that limited demo time might actually increase your enjoyment, although it would make constructing anything notable tough. There's very little "game" in Minecraft, so when you are set to the repetitive tasks in order to progress on projects of your own devising... it becomes a bit tough to keep at it.
Anyway, if you pony up the dough, let us know how you like it and maybe I can visit your world someday!