I should make one thing clear, as it does not seem to be outside the IETF.  There is only one official version of SIP: that presented in RFC 2705.  BUT, just as SG 16 works on successive versions of H.323, the IETF is working on the next version of SIP.  It is the discussion of what should be in the core specification next time around versus what should be in various extension documents which may be causing the confusion in people's minds.  BTW, it seems to me that extensions are roughly the IETF equivalent of ITU-T options.

That said, I agree with Bob that all that came out of the discussion was a feeling that the terms of any such work need to be hammered out, plus a willingness to consider further contributions so long as they don't get too detailed.

Looks to me like this work is going to be done in TIPHON and the interoperability consortia.  Neither the IETF nor the ITU-T really seems to want it at this point.