I wish Sony would come out with a model that takes SD cards from the front.
My wife rides a Softail Deluxe and we've been through all sorts of things trying to get her music situation sorted out. Installed a "Ron's Road King Radio" setup to the backside of the windshield, worked OK for a while, but the radio being mounted vertically didn't lead to long life with the CD drive in it. 2 more failed head units later and I was ready for a better solution.
Ron's Road King Radio ...
http://ronsmotorcycleradiosystems.com/about.php
Went to the old reliable Crutchfield's catalog and found a high output Blaupunkt head unit that did away with the CD drive in favor of an SD memory card slot.
Blaupunkt Brisbane ...
http://www.crutchfield.com/S-cj3H2Y8sGZx/p_023BBANE48/Blaupunkt-Brisbane-SD48.html
She's been running this setup for a couple of years now and absolutely loves it. She's got a 2 gig SD card for it, and it's very simple to pull the card, bring it inside and load more or different MP3's on it, I think we figured out that it would hold around 500 songs. I think she gets more volume out of this setup (with Alpine speakers) than the Harley baggers with HK stereos and Hogtunes speakers. If someone would come out with an adapter to control this unit with the handlebar controls on my Electra Glide, I'd buy that setup tomorrow!