confuscius - 8:45 pm on Aug 23, 2011 (gmt 0)
I have had an identical situation - a number of non connected sites sharing a single IP with some other sites of mine that were not affected. My 9 year old retail site banned overnight and I have not touched a thing in 2 years on it.
I have also systematically dismantled one site all the way back to one page of content with several requests for reinclusion and all you get back is the standard Google response of go and have another guess at what is wrong but we are not going to help you other than repeat what we said last time like some single brained cell amoeba.
My advice, start again on a new domain and do not be surprised when years of hard work gets dumped. Next time round, just spam the hell out of Google with cruddy pages as that seems to work better than anything legitimate.