Mark 1 Jaguar wheels have the same spider size as a Twin Cam and are 5" wide. As the Dunlop four wheel disk brakes were used on the Jaguar D-type the brake parts and wheels are interchangable, but they are bloody scarce and expensive when you can find them.

For wheels which are much more readily available, consider fitting Volvo rims to the Twin Cam spider. They are a loose fit - maybe 1mm oversize, easily packed with sheet metal prior to welding and not too great a gap to bridge. The wheels to use are Volvo 164 sedan 15" X 5" wide or 165 wagon 15 X 5.5" wide. These are a modern safety style rim with the bead groove for tubeless tyres and therefore do not look entirely original. It may be a bit embarrassing to admit to using Volvo parts on an MGA but it is a convenient source.