I am also interested in moving Max2Play to a USB stick/drive or SSD, albeit for different reasons. I have not yet had any SD failure issues, but realize that SD cards are not ideal due to their limited write cycles. I use M2P with LMS / Squeezeserver and have a very large and frequently updated music library. Hence, LMS needs to routinely rescan and write new data to the card, and this will eventually lead to problems. Additionally, I would expect a performance boost via USB.
Have you been able to make any progress on your investigation yet?
Thanks and best,