I looked through your code, however, it does not provide any clue as to what might be the cause for the problem. It is impossible given the complex nature of your implementation to pinpoint that. Therefore, I'd suggest you the following:
1. Isolate the problem in a smaller, more manageable and runnable sample. The one important thing you should do is to bind the grids to a dummy collection of objects that have the same type as those returned by the web services so that we avoid the additional complication of setting up the latter.
2. Open up a formal support ticket and send your files.
It is essential in your case to provide us with a runnable test project that can be debugged on our side. Once we receive the files we shall inspect them, test them on our SP 2010 installations and get back to you with more information.
Thanks very much in advance.
the Telerik team