Thanks to a FUBAR on my part and losing my carefully crafted addressbook on my MBP, I did some looking into finding a way to do time machine backups without spending $600 on Time Capsule and utilizing my already existing NAS device. Turns out that Time Machine with SMB and NFS Shares is very possible with a bit of diddling with settings. This guy got it working with remotely mounted AFP, SMB and NFS shares on a random NAS device.
Also looks like there's an addon for DroboShare via the DroboApps SDK called BackMyFruitUp to add Time Capsule like capabilities, which looks to have potential too.
Now I know what my project tonight will be!