A personal recommendation from me to you, DUNGEONSTONE! I have, as ducats allowed, built up quite a bit of dungeon bits. It is very hardy resin, and damn easy to paint! I just ordered some additional bits and really need to keep painting up what I have already...man I need more hours in the day! Anyway, it's good solid material and at some point, maybe when I am play testing Grim Venture, I'll post some picks of it in action.
A bit about Grim Venture. Not sure if you've played the video game Dark Souls (see my take here) or know much about it, but it is very unforgiving. While I do not plan on making it Grim Venture an unplayable, room 1 your dead experience, I do plan on making it tough. Bad or dumb decisions will kill. Exploration and searching will be important. In all honesty its probably a 2014 project at this point, but I look forward to making it happen and my wife's already done the cover, so I am on the hook to make it happen.