I've asked for the CDL feature before, but maybe it didn't get noticed. Don't remember about about the logging stuff (mednafen has logging, but it's not like fceux or other trace loggers - snes9x, etc). I've asked for stuff in the past, and donated $50 each time for them. But I'm broke nowadays. $50 won't cover the time it takes to actually write the code for this, but it's something (better than nothing). I haven't talked to her in while, so it's kind of a jerk move to say "Hey! Been a while, btw.. please add blah-blah-blah to mednafen for me".
Bizhawk might be the way to go (it was the fork of mednafen emu for windows, with gui and recording), since it's geared more towards that. Might be able ask/request for FCEUX features for it. I got a couple of features put in - from a request, before the name change.