You're all a bit confused.
* Kernel 2.6 works _very_ good on C7x0 thanks to the OpenZaurus kernel hackers, including the (unaccelerated yet) W100fb and SD/MMC.
* SD won't be possible on the SL5000 and SL5500 unless someone with huge expertise dives into the locomo interface and gets the NDA documents from Sharp.
* Alsa or OSS is not a matter of generic kernel, but of drivers. At the moment, many PDA sound drivers are still OSS, because someone has to write alsa drivers.