The aluminum wheels Jeff pointed to from Singapore Hobbies are probably also made by MPI. They are very nice anodized aluminum hubs with nylon inserts for various axel sizes, and have a high density thin profile sponge tire with a rubber rib for support.

You can get the same set in the US from MPI, except anodized in gun-gray instead of red. I've used these extensively on classic pattern with great results. Many retailers sell them, and they are priced much cheaper than Tettra or MKs:

http://www.rcdude.com/servlet/the-56...b-Light/Detail

Matt