FWIW, we find that people chuckle over the Spam module even if they ultimately ask us to rename it. I suppose there are some particularly uptight management types out there who wouldn't see the humor in it (probably more than I'd like to think) but for those who do get it I think it makes the toolkit a bit more approachable, gives it a sense of humor.
I'm not really opposed to renaming it if the name is causing problems but thought I would present the other side. If I were choosing a name I'd call it "bulk mail"; short and to the point, as most of the module names are.
The easiest way to solve this is to add a package param to replace the word "spam" everywhere it appears, and point out to the prospective client that you can now mount it under any name you choose, so there's no reason for any user to ever see the word "spam" if they don't want them to.
