The short answer to your question is, yes this is all doable and has been done several times. In fact, it's fairly short and simple work.

The real question is: Are you wanting an off the shelf solution (IE: Someone else wrote it and your going to use it) or do you want to make your own?
The other real question is: What language do you have for your hosting environment; PHP, .NET, RoR,

This plays a difference. If you have PHP and MySQL and are wanting a fairly off the shelf solution, I'll post up the stuff I've been working on for you to do as you please. I have to admit though; its rough but robust as I hope to use it across all of my projects eventually.

- Jeremy