Hi All -
We have put a partial/draft list of SSA implementations (libraries/toolkits, services, clients) on the SSA RFC page:
http://www.ivoa.net/twiki/bin/view/IVOA/SsaRFC
This is needed as part of the RFC/REC process. This is based upon a very incomplete and in most cases probably out of date understanding of the status of these implementations, so it is probably full of errors and omissions where *your* implementation is concerned. Please feel free to edit this as desired if you have an SSA implementation you would like listed here.