Dear johnbock,
The denx u-boot git now add mvsata support on orion and kirkwood.
A sheevaplug esata support can simply be add with a patch, posted on the denx mailing list.
This uboot works on newit esata sheevaplugs with a debian squeeze from a sata drive (debian installer and official debian kirkwood kernel).
The only modification is in the env parameters :
you need to do configure machid env variable with the machine id hex value.
