Supporting 6 drives would be a little much for a home user. 4 would probably be more likely. Also i can pretty much guarantee that the whs you're using is a serious power hog. Housing and running 12 drives would require some serious cooling and power. 6 would be quite bad as well really. I agree with supporting various sizes and parities though.
It doesn't really take as much cooling and power as you would think.
I have a Home Server with 8 Hard Disks, the case is cooled by only 2x120MM fans and each drive according to its own SMART monitoring system is around 24c to 41c (As not all drives are directly infront or behind 120MM fans so the temps vary) The drives I use are certified for operating up to 60c (Samsung 1TB's) Those temps were taken under extremely high load on all drives so I would never expect them to get any higher.
Power wise each drive will consume 6 watts Idle and 12.5 Watts at maximum I/O load. Equating to just 100Watts under full Load. With the CPU (45Watt Model that spends most of its time around the 20Watt range) Raid Card (10 Watts) and Motherboard (35Watts) with 2 Dimm Slots and no Graphics Card the entire system comes at just 165Watts @ Highest Disk Load. With a Maximum power draw of 200 to 210 Watts if the entire system (CPU and all) were under maximum stresses. A Home Storage server spends most of its time Idle though or with only mild disk access, Which would average out the power consumption to around 113Watts. I have in my Server an ultra-quiet 520Watt Tagan PSU and overall the Server is very quiet and low power but I get some excellent performance 60-70MB/ps Read and Write over the network with over 200MB/ps read/write on the local system with benchmarks like HD-Tune.
Now obviously I don't think the average home needs a 6 or 8 drive NAS. Two and Four drive Network Attached Storage devices is all that the majority of Consumers need but there are Prosumers out there who do need lots of storage, be that to backup large quantities of Digital or Physical media to saving personal projects, photos or video. Hell if you have a Windows Media Centre and you regularly record High Def through it your eat through gigabytes of storage per day.
I'm quite happy with my NAS as its expandable to 16 drives and thats what I wanted when I built it, expandability and high performance. But I think Apple could definitely shake up the market with a 6 to 8 drive unit because there really is a market for it. If you look at the NAS's available right now in the 4 drive region they mostly run on ARM processors (like the iPhone) and use Software RAID for data integrity. These processors are really slow for doing RAID5 calculations and the performance is not very good. Alternatively you have products like the Drobo which has a more beefy Intel x86 processor but its crippled by a 100Mb ethernet connection (Which is only capable of 12.5MB/ps transfer speeds)
I do think Apple could shake the market up but I don't think they will. Their recent products have been quite ... unremarkable. They seem to be aiming for Size and Weight more then Performance. I remember a time when Apple loved to spout how the PowerBook G4 was the fastest Notebook in the world and then they brought out the iBook and compared it to $1000 Competitor notebooks that were just not as fast. I think having let go of the performance crown and aiming for a size and weight margin has hurt Apple in the Prosumer and Buisness area where Form isn't a factor in a purchase decision. You don't buy a Porche to plow a field because its sleeker then a Tractor and with Apple only releasing 2 or 3 products in a range it limits the markets that would want to buy those products.
To elaborate what I mean exactly, if you look at their Desktop systems you have 3 systems. The Mac Mini which only supports 1 Laptop sized Hard Disk and cannot be upgraded Graphics or CPU wise. You have the iMac which comes with a screen weather you want it or not and also cannot be upgraded, and you have the Mac Pro which is like a leapfrog from the iMac. Dual Processors very large enclosure and very pricey for the ability to upgrade its components. What is missing is a Middle class Buisness/Prosumer tower one with a Single Quad Core processor in a form factor like Prystar are currently offering. Something cheap but fast with full upgradability. And I see this happening to the Notebooks as-well (Removing choice of Matted Displays, DVI, Charging $99 for a connector adapter that no one wanted to buy).
For all these reasons and more I see an Apple NAS as a nice addition to a family that already had / wanted a Time Capsule but nothing that will make us geeks hearts flutter and that is a real shame from the little Apple company I love.
I still haven't even ripped half my DVDs.
