I'm really into computer aided drafting 3D modeling and found that a company called Shapeways will take your 3D drawing and print it for you. TDR Innovations has been using them to print their products they offer, and I've purchased a few things so I know Shapeways does a good job.
I'm offering my free time to create any more generic parts that people are looking for, such as mufflers, hitches, pulleys, and so on, as well as some wheels. I know in one of the 'Cuda build threads, people were wanting a Flowmaster muffler that the original poster had a friend make, but only had a few made total.
So if there's something that you'd like to see made, just post here and I'll let you know whether it's feasible for my skill level.
Also please mention scale when making suggestions.
For wheels, please provide rim diameter (not lip, but the rim that fits in the tire) and width.