Blending languages would be nice, although I'd be happy with files being in one language but projects being in multiple. So if I find a neat class on the web that's in C# but I want to use it in my VB project, and I don't want two DLLs, I don't need to translate
the C# to VB (and inevitably introduce errors).
Just integrate ILMerge into your build process.
But is translating from VB to C# and back really that hard? Given most samples I see online (like on CodeProject) are in C# I think it'd be better to use C# anyway. The only VB samples I see are for trivial things because the people who consume them are
beginners who are still finding their feet.