Bike Island has good prices; so does Velomine.
This is pretty sweet if looking for 130 mm rear:
http://www.velomine.com/index.php?ma...oducts_id=2723
There are not a lot of choices out there for new wheelsets if looking for 126 mm. Tough to beat these price wise at $109 but they do take a freewheel:
http://www.velomine.com/index.php?ma...oducts_id=2114
You can find an indexing shimano compatible 7 speed freewheel for your ironman.