On the Font Limit in sigs, I belief the history of it can be found here, under June 28th 2001 http://users.tkk.fi/~mmlankin/SB/History/
Only thing is that it's impossible to gain access to the announcement, so I'd have to trust word of mouth here. :(
Not the best source, and fairly old. Did find Douglas Nicol posting a few warnings (from 2002) that sigs were to be 5 lines of normal sized text at 1024. Edited the summary somewhat accordingly.
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