I've just put a new version of the http://mastercoin-explorer.com online.

This version actually has some useful information. For one it can approximate balances for a given address and show what kind of transactions where done by them. As always this is an initial version of this functionality so don't expect any miracles

J.R.: I spend way more time on this then I originally planned. So to be honest I hope there will still be a bounty for something like this even if I build it already; not that that was the reason for me doing it to begin with