is there an add-on that would allow a short recording of a boss fight? i realize there's probably another program you'll have to run with as well but im not sure what add-on to get with it

There are a few programs you can run to do this, it's not something that an addon would be able to do I dont think, there are a few options.

Fraps is one good program to get, another is in beta called WeGame which records well but less controls over the actual quality, still should be reasonable enough for youtube etc.   Of course there are others, but these seem to be more popular from what i've seen

If you have a Mac, the built in UI has video recording options for hi-def Quicktime; for Windows, what Private said.