Woobious (Swombat's startup) has been in this space for while. I am rather surprised that they have not done stuff with the tablet form factor.

WoobiusEye is http://woobiuseye.com/ is practically made for the tablet.

Edit to give feedback on the site: ==================================

It would help to have screenshots of your app to show (Architects are visual)how it is different from any normal document manager. I guess it is, but I do not really have time to download and find out.

It is a good idea, addressing a big market. Good one.