I've been on a SWBF2 nostalgia trip recently and watched some old YouTube videos from GamertagTowellie of the Xbox version of SWBF2 and he has has a few of online clan matches.

I was wondering if anyone here played the Xbox version online at all, knew anyone that did, or could help me find if any of the Xbox clans still exist.

I doubt any still exist. It was played over Xbox LIVE, and the version of LIVE that was on the original Xbox has been shut down since April 2010.

Right, but if I remember correctly you could transfer your Live account between the original and the new Live during the first 2 years or so. I don't have a 360 or X1 so I can't check the account names in the videos to see if any are still active. I know a few clans from the PS2 version that transitioned to the PS3 and now PS4 successfully with mostly the same people. I was wondering if any Xbox clans did the same.

I image that any Xbox clans played more than SWBF2 though, likely Halo 2 as well. On the PS2 it was either SWBF2, SOCOM, or BF2MC but mostly just SWBF2 because the target audience for SWBF2 and SOCOM was completely different.