Raaaaaaaaaaage! Lol. That really sucks. I've had to do social marketing for a few businesses who had this problem. Here's what I recommended them:

- Post in your own name. Can be advantageous, gives you a person layer.

- Use an @ name. For example, if your name is Joe, and your brand is OzSocial, use Joe@OzSocial

- Make a variation. Use an underscore if 2 words or a dash.

Keep in mind you still might have issues with users searching on Twitter, but if you can integrate Twitter with your site then it shouldn't be an issue.

EDIT: Should mention, I doubt Twitter would remove an account for ya.

I don't know, find a new username instead. One that's nicer than the one taken.

Twitter Username TAKEN!
 

I want to use a particular user name on Twitter, however some douche has it....

They aren't following anyone, no followers & 6 tweets, and they were all back on Sept 2010

It's a bit annoying. Has anyone contacted twitter before to see if they can use an inactive twitter account?

I can't say the same because my twitter name is pretty unique, but generally I'd suggest changing your name slightly. While keeping the spirit of the company of course.

Sorry, moved to Social media

Hard when it's the exact business name :|