Really incredible work. Is there anything we can do to speed up exporting, short of manually parallelizing across multiple computers? Distributed export might be a nice feature.
When I first started using tilemill, I missed that you can create indexes for shapefiles. This turned a 12 hour render into a 15 minute render for my particular use case. The devseed guys show how to do it here : http://developmentseed.org/blog/2011/mar/29/speed-optimizati...