Hi AG
Hmmm as far as novelty prints I have a very hard time finding motorcycle related fabric let alone trikes. I'm not sure such a beast exists.
You may want to try making a T-Shirt quilt instead. Ask the club to donate a shirt or two each and cut out the imprints on them, back them with fusible interfacing slap a sashing between the blocks and wah-lah. I have made numerous T-Shirt raffle quilts for my motorcycle club that way and the T-shirts have such great motorcycle screen prints on them. Usually turns out very colorful and always raises a few hundred dollars.