I've seen a couple of TBAs with Honda Ace front fenders on them... looks a lot fuller and if you're into chrome you can then put the chrome fender guard on it too. (And you thought Triumph chrome was expensive? Wait till you see the price of that piece!)
3spirit had a
thread recently where he discussed how he's laced a wider rim onto the standard hub and put a 130 front tyre on.

No guarantees that the honda fender & 130 tyre will work together, but that's what customs bikes is all about - experimenting. If everything was already tried and guaranteed it'd be called "copies of custom bikes".

Matt