What to look for in a aftermarket (mag style) trailer wheel?

[moose-hunter]

A buddy of mine is reconditioning his trailer and wants to buy all the wheels/tires off my Shoreland'r. UPGRADE TIME! I can finally get rid of those nasty looking gray steel wheels and marginal tires for something a bit more aesthetically pleasing and safer. But...

What and where do I look for aftermarket trailer wheels? I'd like to match the wheels on my truck but will truck/automotive wheels work on a trailer?

I know... Seems a bit superficial but if you can, what the heck... right?

Any advice on new wheels? Aluminum? Steel? Unobtainium?