I'd be curious about this as well. I have an older PC that I would like to put at my parents house for their WHS use, but would also like to have my critical files duplicated to there as well. Sure I back up to external hard drive, but I have no good place to store it. It's in my house away from my WHS until I go to backup, but if my home had some major catastrophe, I'd lose everything (paranoia I guess, but something to plan for).
Wonder if you can run a connector disk from one WHS to another? As long as you had it through a VPN I guess it could work. But maybe WHS won't accept the connector disk. I dunno.