That site sounds like a good idea! I guess I should update my own site and send you the html files for my addons.
As for the older versions of drivers and software, rather than having them all, you should probably limit yourself to the ones that people recommand for special cases (i.e. use driver 1.23 because they introduced a bug in the following releases, etc.). For BTV itself, I can see a need for 3.6 ("Internationnal version"), 3.7.4 (last release before 4.x?) and probably a link to the latest version.
Once everything is setup, it would probably make sense to have everything hosted by SnapStream, this way you don't have to pay for the bandwith/hosting and should you stop working on it (other priorities and such...), it would still be available.