Hi David,
Yep use them, have a couple of deployments in conjunction with Syncsort and their DPX software (or Syncsort NSB when put together with the NetApp back end)
So use exactly that config a 2240 single controller, then take advantage of dedupe and compression to deliver the storage efficiency solution you are used to in the production environment.
It works a treat in those environments and with Syncsort, delivers a really nice single backup solution (so removes TSM and Veeam for example).
You other option is to use SnapVault In that environment, so a full on NetApp only solution to deliver both primary storage and long term backup and archive as necessary.
Hope that helps.
Regards
Paul.