Give this a try. It is a quick render queue script that keeps prompting you for Vegas project files until you hit the cancel button. Once you hit cancel, it will render all the projects you chose. I recommend you read through the script first and set the variables (which are commented) to suit your needs.

I know there are plenty of ways to improve this script and I'm open to ideas but I just wanted to get it out there to show that it can be done and solicit some feedback.

B.T.W. I've begun a Vegas scripting FAQ which may answer some questions about using and creating scripts.