So - any suggestion on what that might be?
Bob
First off, a disclaimer. I have not used any of these devices nor tested any configurations that I list. I'm simply going off of what I've read.
The lacie eSATA hub is pretty cheap (for a TB accessory) at only $199 + cable. But it's really only useful for adding the second monitor and if you have eSATA hard drives.
The Belkin Thunderbolt Express Dock is $299+ cable and adds additional GigE, FW800, USB 3.0 and Audio in/out ports to your setup. It supports TB passthrough, and can be found here:
http://www.belkin.com/us/F4U055/p/P-F4U055
Setup for the belkin would again be:
MBA <- TBD <-Belkin <- Dell
If you want just a hard drive, there's the Seagate Thunderbot GoFlex Hard Drive for $300.
Amazon Link. Seagate actually includes a TB cable so that saves you $30-50. It's a 3TB drive with a TB Dock.
Finally, if you are patient, there's the CalDigit Thunderbolt Station, which, although not currently shipping, is supposed to be $199 + cable. It has almost the same ports as the belkin, but drops FW800 in favor of HDMI. Personally, if this one works, I'll likely pick one up when it starts shipping.