Hadn't seen any mention of this in the forums, and thought I'd share. Apparently D-Link, the manufacturer of the Boxee Box, intends to sell this remote by itself, as well as bundle it with the box. Seems to me it'll fit in quite nicely with LinuxMCE, barring any proprietary shenanigans.
http://blog.boxee.tv/2010/01/05/by-the-pricking-of-my-thumbs-something-awesome-this-way-comes/ (http://blog.boxee.tv/2010/01/05/by-the-pricking-of-my-thumbs-something-awesome-this-way-comes/)
Thanks for the tip, I'll be getting one of these!
I should add that I contacted Linksys about the remotes and availability, but never got a reply.