Has anyone actually developed a C# dll in Visual Studio 2010 that could be registered on another pc via regasm?
Yes, someone has done it.
Look at the documentaion on creating an interop DLL to see if there’s a step you may have missed. A common problem is forgetting to set the ComVisible property to true in assemblyInfo.cs.
Some key sections:
solved How do you develop a C# dll in Visual Studio 2010 that can be registered on another pc via regasm? [duplicate]