Hi,
Marcus started to go in this direction (CoverageStyler). With MetaLinks we will be able to do that soon quite easily. I'm currently working on per-method coverage testing of the minimal Pharo - mainly because we need to know what tests that we already have need to be moved to this image. However in this case I export coverage result in form of one huge JSON document that will be processed by a single HTML page with a simple Smalltalk-like browser (with colored rows etc.).
Currently we are able to check and show methods coverage using the code simulator (that doesn't work well with exceptions):
Cheers,
-- Pavel