I have been meaning to take a look at the EMC Rainfinity product for a long time now but never got around to it. EMC have now released it as a virtual appliance which you can get from Chad’s site here. The link also provides info on the product as well as installation steps.
The VE edition is free for non production use but there is a paid version that could be a great solution for SMB clients who have data archiving requirements if the price is right. The biggest benefit I see for SMB clients is reducing the amount of data that needs to be backed up.
I’m not sure what targets and destination storage it is able to work with just yet but after having a play with it I will post again with my findings.