I did manage to get it installed.

I logged into the tablet with ssh (OpenSSH) (as root) and used apt-get install skype to do the install.

I had to accept the license agreement to install on the n810's screen -- which confused me because it was blanked at the time, and I didn't know it was setting there waiting for a confirmation for 5+ minutes.

Anyway, it is installable. You just have to 'cheat' a little to get it to go. I should be smoother than that. Most users won't keep trying -- much less use the terminal and know the apt-get command line interface.