I made a freckled face texture, and made a copy of the Caucasian race with the new texture. However, when I attempt to use MatchRace to change my char's race to match the race of the match source NPC, it does nothing. I can MatchRace my char's race onto the freckle race source making it vanilla (albeit modded) Caucasian, and I can MatchRace Dr. Li's Asian race onto my character, but not this mod-added NPC's race.

So is MatchRace bugged when it comes to mod-added races and the Player char?

A quick search on http://geck.gamesas.com/index.php/MatchRace yields a few threads. http://www.gamesas.com/index.php?/topic/1051242-bad-matchrace/ seems to describe a situation where M3hdi tried to change the player race into a custom race with custom textures. While no solution is given, one could try to esmify the mod with the races? Uglulyx had a similar problem in http://www.gamesas.com/index.php?/topic/1072801-trying-to-change-the-players-race-using-matchrace/ and there are a number of interesting points and ideas. One interesting idea is to ensure that there are child (and possibly old and oldaged) versions of the custom races. You may also find http://www.gamesas.com/index.php?/topic/1106990-duplicating-the-player/ interesting.

It should also be noted that the only Fallout3.esm usage of MatchRace is to match the race of James ("daddy") to the race selected by the player, using these lines

		; dad matches player's race and face		MQDadREF.MatchRace player		; match face		MQDadREF.MatchFaceGeometry player CGMatchFace

The NPC needs to have 'Can be all races' checked in the editor for the function to work, and the player doesn't.

A cookie piece of toast for Toaster... that did the trick.