Will and SAN built for AVID also work with FCP 7 and Premiere Pro

I'm in the market for a networked storage solution for a small 2 man shop. Right now we're editing on FCP 7 but we're exploring moving to Premiere Pro or AVID but haven't decided which yet. I know AVID is very strict about the shared storage systems that it will work with and Final Cut/Premiere are not, so in the interest of covering all possible scenarios, is there one solution that works with AVID's picky design that FCP 7 and Premiere would have no trouble with?

We're using 2008 MacPro's and we typically cut DVCPRO HD 1080i or Apple ProRes 1080p. Right now we keep all footage on external hard drives and transfer that to an internal Media drive for cutting but we would like to be able to cut from the shared storage. We're never working on the same project simultaneously so that isn't a concern for us.

One more question before I go:
We shoot about 12.5TB of footage a year but we need backups for everything so our annual total storage size is around 24TB. We rarely need to go back and grab footage/projects that are over a year old (rarely but it does happen) so I was considering LTO for projects/footage that are over a year old. Does this sound like a good workflow? Does anyone else work similarly to this? If I were to find a networked attached storage system that could hold around 15TB and it was configured in a Raid 5 or Raid 6, wouldn't that eliminate the need for backups?

Please let me know if you need any more info. Right now I'm just trying to get a general assessment of my thoughts so I can pass along to my company's tech guy who doesn't know much about video but is well versed in networks and storage.

Thanks!