In this blog I connect the space vs MTTDL models with a performance model. This gives engough information for you to make RAID configuration trade-offs for various systems. The examples here target the Sun Fire X4500 (aka Thumper) server, but...
The ZFS lovefest continues with this slice of use-cases and sample commands for a ZFS archive for "home" use. I am sorely tempted to get in on the action, somehow.