This is cool, and I kind of wish it was released a few months ago. I've been building something like this from scratch for a work project for a little while now. Did you guys look into using an actual <table>, or did you go with divs form the start?
We were using Slickgrid for a while and that was a very painful experience as the code was very complex, didn't do frozen rows/columns and didn't interoperate with Ember nicely. I think we wrote this with div's from scratch.