>Can a component written in C# (Winform) be called from within vfp7? Are there any issues? IT decision-makers in our company wants to do that, but nobody here has ever done it before. Any comments appreciated.

Yes, and it should work fine just like working with typical COM objects from VFP. Check out Rick Strahl's whitepaper below:

Using .NET Components via COM from Visual FoxPro (or other COM client)
http://west-wind.com/presentations/VfpDotNetInterop/DotNetFromVFP.asp