We are rewriting right now in c# and Silverlight. Our development timeline is 9 mo (with 7 developers) to product on the street.

Have you considered what you are saying? The above compared to a $250 compiler that would allow you to recompile the existing app into Silverlight 2.0 or whatever comes next? Seems very clear to me- unless I'm one of the 7 developers being paid a salary to reinvent wheels, I guess. You'd better hope that there aren't any similar VFP apps out there to suddenly appear as a Silverlight 2.0 app at a fraction of the price you need to charge to cover your overheads.