Simon,
>Are there any tools around which will take a VFP report and create the SQL Server Reporting Services RDL/XML definition?
EPS Software was working on such a tool, although I don't know if it's ready or what the pricing is. The Tools page at VFPConversion.com lists their VFP2NET(Reports) tool, but I can't get the video demonstration of it to load with my current internet connection (maybe a firewall problem).
Anyway, it might be worth investigating with an email or call to EPS.
http://vfpconversion.com/Tools.aspx