Ok, this is kind of pie in the sky and very low on the priority list....but have you ever thought of having the ability to translate a code snippet from VB.Net to C#? The online conversion tools generally work remarkably well for this. It may be a bit controversial offering something targetted only to specific languages, but I don't know if anyone would get that upset, would they?
A cheap way to do it would to contact one of the third party vendors, tell them to write the API, and you can just embed into the SO UI for anything tagged C# or VB.Net. In exchange, you will show a "translated by xyz".