I never said anything about SD cards. I have a GS2 which I have a 32gb one in and hookup indirectly to my system, but that's about it.
I did, however, mention my usb port. As I said, I a lot of flexibility with it...
I can play anything from just about any source at any time.
USB Flash (and obviously anything with a USB adapter like an SD)
AUX (any phone?)
AD2P Bluetooth
Pandora/Slacker, etc. (via BT or AUX)
iPhone/iPod direct connect (although I loathe APPL)
Storage is not the issue, it's the price, that being said...
I would only get some sort of Samsung tablet, etc. running ICS at full HD, with usb ports (which I would then have the flexibility I currently have and outlined above). I would NEVER buy Apple as they are closed source (no removable anything, no rooting, etc.)
Sure it's more work, but anyone even looking at this forum understands that it's rewarding to work on a project and get it done the way you want it. I am the only one of my friends with an aftermarket stereo period, but that won't stop me. Most listen to ripped CDs at 128kps while I have 200lb subwoofers for my home theater at home. Different strokes indeed.
My only point was that for $1,500 you can get a good tablet at $600 and then upgrade again in a few years and for another $600 while still paying $300 for a really nice fiberglass install (if you really didn't want to mess with it yourself). This way you'd have an asset that's mobile and even more flexible (updated Gmaps, wifi) for the same price.
Something like this:
370z Cubby Tablet - YouTube
And as said, it you wanted it nicer instead of some 3M fake carbon ndoc or w/e, you can take the money saved and do so. Give it 2 years and Scion will have tablet screens that can be detached.