There are tons of very obvious problems in many industries that are solvable by software. The only problem is that great domain experts and great hackers rarely overlap enough to do a startup together. It was a miracle that the four of us found each other.
Just read the "About" page on the PlanGrid site, and indeed your team does seem to be a great combination of experts & hackers.
My background sort of puts me with one foot in either camp for this particular problem set; it would be really cool to chat with you folks some time when I make it out to the Bay Area.
