Microsoft Office - Replacing Clippy with custom characters?

[Thylacine]

I'm curious if it is possible to make your own Office Assistants with relative ease. I was thinking along the lines of video game sprites, which may or may not be animated. Is it possible that this could be arranged?

I'm not much of a guy to perform massive OS surgery, as I'm one of the few who can keep Windows relatively stable in most situations. If this requires massive reformatting or anything too intense, I'm not interested.

[The Damned]

"It'sa me, aMario! Ita looks like yous want to write a letter. Woulda you likea som help?"

[Thylacine]

"It'sa me, aMario! Ita looks like yous want to write a letter. Woulda you likea som help?"Something like that, only no bad Italian accent.

EDIT: I think I found something: http://www.microsoft.com/Msagent/downloads/developer.asp

This looks like it'll do the trick. Stumbled on it quite randomly. Thanks anyway! :)