Now I have had the DreamPlug over a week I will share the issues that I have had with it.
1. uboot prevents booting a kernel from the SD card. You can load the kernel from MicroSD or Usb. The rootfs can be loaded from an SD without any problems.
2. Sound channels seem to be working in opposite phase and canceling each other out. If you select Left or Right balance on the sound mixer each channel on its own sounds normal. I think this is a driver issue perhaps someone else could comment on that.
3. Sheeva.with-linux kernels beyond 22.214.171.124 do not boot. Something changed at 2.6.36 and is still present at 2.6.37
The boot process halts at this line:
loop: module loaded
Could it be to do with it having no Nand? on a succesful boot the next line reports;
No NAND device found.
Would be nice if this was indentified and fixed.