If you use uuid prepending on your logging to help you grep out a call, Math wrote a patch to apply that to the multi-line SDP, too.
(See http://wiki.freeswitch.org/wiki/Mod_logfile#Logging_UUIDs for how to turn on)

If you can test it out and comment, the patch is here: http://jira.freeswitch.org/browse/FS-3572

Also, there's still at least 4 log types that don't get the UUID, I unfortunately still don't know enough of C & FS to check for myself why:
2011-11-03 08:41:12.696695 [INFO] switch_nat.c:589 NAT port mapping disabled 
2011-11-03 08:41:12.876687 [DEBUG] switch_rtp.c:3181 Correct ip/port confirmed. 
2011-11-03 08:41:12.736698 [DEBUG] mod_local_stream.c:421 Opening Stream [moh/8000] 8000hz 
2011-09-16 15:44:06.776690 [DEBUG] switch_core_file.c:180 File .....v3f.wav sample rate 44100 doesn't match requested rate 8000



-Avi Marcus