There is no current product out there that will do what you want. The Matrox MXO2 line (non-Thunderbolt) is perfect for you.
Connect via Express34 and get a FW800 Raid such as G-Tech RAID Mini.
When I travel, I use that configuration on My 2011 TB 17″ MBP with MXO 2 and it performs very well.
Steve Eisen
Eisen Video Productions
Vice President
Chicago Final Cut Pro Users Group