While I agree with Jim that multiple snapshots would be desirable I would have thought it beyond the scope of customer the ReadyNAS is aiming at.
For instance an 8 snapshot scheme from HP on the MSA 2000 costs around £600 for the licence. (This is SAN based and works at block level rather than file level).
I would also suggest that the Daily, weekly, monthly model is not how snapshots are generally implemented; most companies will be looking at multiple snapshots to cover systems on an hourly basis or better, longer term solutions are usually handled by D2D or D2D2T. Multiple snaps are taken up by companies with a need for a short 'Recovery Point Objective'.
Using a 2nd ReadyNAS also makes sense as this is not for snapshot, this is the equivalent of Volume Copy or Cloning. The only way of achieving this within a single ReadyNAS would be if there are separate volumes on it.
Just my two pennies... I'm not working for Netgear, in fact I am a HP Enterprise Storage Trainer, bigging up the ReadyNAS is probably considered a bad thing
You should all ditch them and invest in Storage Servers