Unfortunately on two machines that I'm using that i7 cores, 16GB of ram, they both seem to have performance problems with layout recalculation.

Also I believe that many problems that this is trying to solve is already alleviated in existing technologies that will work in modern browsers, including IE10+, and web documents do not necessarily need constraints.

I think contributing to Mozilla or Webkit, or proposing a specification to the W3C would be more advantageous for your cause.