I'm having trouble figuring out how to change a companions race. I downloaded a custom race and want to apply it to a downloaded companion. Bot the companion and race file is an .esp. I've tried everything I can think of, making a new .esp to load before and after the companion .esp, save over the original companion .esp (backing up all files first), replacing the companion .esp but nothing works. I even tried to modify a default companion (Cass for the record) and it still had no effect.

In short my question is how do I change the race of a custom downloaded companion with a custom downloaded race (skin texture)?

The easiest way seems to change the race mod to an .esm and make the companion mod master dependent of this .esm
Or if it is only a different texture you you can create a new race using the texture in the companion mod and don't use the race mod.

Hmmm sounds like I would have to take your first suggestion. Could you tell me how to do that or point me towards a tutorial. I thought of doing that before but I'm new to GECK (obviously lol) and don't have the faintest idea how I could do such a thing.

There are several tools to change the .esp to a masterfile
Personally I use : http://www.newvegasnexus.com/downloads/file.php?id=39655
Once installed it is very fast to merge plugins or to convert .esp to .esm and the reverse.
I am used to this small utility since Oblivion but someone else can probably suggest another one

Wrye Flash and TESsnip (part of FOMM) will do the same thing.