Add another while you're at it. We're about 50% Macs here and I would love to use LogMeIn Backup on our workstations and servers. This may take another 20 years at the rate the Mac side of it is going but a Linux host would be extremely helpful as well.
I've never actually tried this, but you could try using PsyncX on the Mac to sync files between the Mac and a network share hosted on a PC. Then use LogMeIn Backup on that PC to backup the shared folder, and you should be good I would guess. Definitely want to test it first before counting on it working though.