Pledging some of the add-ons. $10+ whatever seem to me the non-crazy way to go. The only thing I want out of the main dungeons is that circular room but it is too rich for me to be buy in that level.
I have the same storage problem with my existing Dwarven Forge stuff. :-( The price for some of the cooler looking parts is pretty high too. I'm going to try to resist. We'll see how that goes. Great looking stuff though.