Puppeto, if you already have the Rial caps and just want a smart logo on them, check out:
Making it Digital - Emblems
I had a set of custom VW emblems made for my GLI, and they came out beautifully. You'll just need to measure the diameter you need, and most likely provide him with the proper logo you want. After that, you can choose any colours for logo and background, and the whole set of four only cost roughly $20. They come with a very strong 3M adhesive, and proved to be quite durable with their UV-resistant top coating.