"is pretty surreal. . ." --tell me about it =) Frankly, I think it's too many features. We've a prioritized development schedule based on user input, and I expect that we'll find that the site becomes what we want/need at around 1/3-1/2 of these features.

That's good to hear, about Django, given the prominence of user/session support in our plans. Public site design is frankly a secondary concern: I think a template system will be more than enough. But, I figured I'd throw it out there.

We've already rolled a simple CAD/drawing app via the element, and I expect that to be more than sufficient.

Thanks a bunch for your input! I'll be sure to be in contact as we proceed.