I do live in DC, and in a spot where good parking and the Cleveland Park metro station are both within 2 blocks. Space for *people* might be a little tight but I would be willing to host a meeting at some point.
Unfortunately I have no cool tanks to look at right now--just a collectoritis 20 gal. BUT, I am in the midst of a 57 gal tank build that should be ready for plants in a week or two. I would consider offering up my tank as a guinea pig for an aquascaping demonstration. As I've said elsewhere, I know a lot about DIY (stand building, plumbing, electrical, etc.) but can't seem to figure aquascaping out.
--sam