You wont be able to run dual 27" Cinema Displays at full resolution. The best you'll be able to do is to run each monitor at half resolution with the Matrox DualHead2Go.
Thunderbolt's 10 Mbps is barely enough to push out the pixels on such a setup. Anyway, since the ACDs use DP 1.1a and so does the MBA, you can't exactly connect both monitors at the same time using the 1 port.
Matrox doesn't have any solutions that can power 2 such high resolution monitors from 1 DP either.
You wont be able to run dual 27" Cinema Displays at full resolution. The best you'll be able to do is to run each monitor at half resolution with the Matrox DualHead2Go.