When I was a grad student, those of us in the lab had this conversation on a weekly basis.

Now I wonder...

NSF has these big cyberinfrastructure programs. I wonder what they'd say if you proposed such a thing.

http://www.nsf.gov/div/index.jsp?div=ACI

To have even a slight chance at success in this, you'd definitely need to have your story straight from the very beginning. You'd need to show a very low-risk plan for replicating all the features of LaTeX that really matter, with measurable improvement in usability.

Probably a super-long shot, but it would be very cool.