Re 2.5in - 3.5in Drive adaptors
There is one available in the US from MaxUpgrades.com Part No:SZ-VRMACPRO-01
It's seems to be the only one on the market, except for the drive adaptor plate that I've developed...
I have manufactured an adaptor plate that retrofits on to an existing MacPro drive sled. These have been thoroughly tested on a number of gigs now and a number of clients have been using them with OCZ 2.5in SSD's with no issues.
The OCZ SSD's also seem to perform well. I've been using the OCZSSD2-1C64G and OCZSSD2-1C128G with HD content. I've got 4 layers of HD with no issues (AIC - 3G 8Core)
Let me know if you need a Drive Adaptor plate (or drive)
Simon