You should be able to find a wheel for that. As said you need to remain in the same number of cogs to avoid frame width issues and wheel size (likely 700c) to avoid brake reach issues. Someone who took a similiar raleigh and converted to fixed gear has one right now. I picked up a '85 Grand Prix at a yard sale for $20 which has the same rim/hub so I know they are out there. The sealed bearings on the '85 are really loose ball bearings with a rubber external seal - piece of cake to replace the bearings and have the shop lace a new rim on if you want to go thet route.