The wheels are too good to toss, but I don't know how they would work on a cross bike. The rims are great light ROAD racing rims, but I'd assume not off-road racing. Perhaps you can unlace the rims and sell them, then buy a set of vintage Mavic GP-4 - a very robust vintage tubular rim.
Or, what about the 730? The nice road wheels were a good match to a nice road frame.