Replying very late, and sorry. The fault is all mine. Seeed hasn't restocked because I haven't funded more kits. The way this works is that Seed is a third-party assembler/reseller. I send them the plans and fund the parts and labor, they put the kits online and handle shipping. Eric and the crew at Seeed has been fantastic and if you ever need a similar service I really recommend them.
I decided to stop the orbshield kits through them for different reasons. First, I discovered that I have sold many of them, but I have no idea to whom--that means getting word out on update and support has been difficult. Second, the first version of the Orbshield had some problems, and I don't know what they were--but about one out of twenty just plain didn't work. I had people send me theirs and was completely unable to figure out what went wrong. Third, the Arduino's design periodically changes and I wanted to avoid trouble there.
As a result, I wanted to redesign the board to put the ATMega328 on the same board as the "shield" to make a one-board device. This would lower cost (no more Arduino required) and maybe fix some of the problems, as well as selling through my own site--for experience's sake and to maintain a community and mailing list so I could send out updates, etc.
Unfortunately life (in the form of a divorce and international move) got in the way of all this happening quickly. Please don't take it as a reflection on Seeed; they're good folks and have been great to work with. I hope to have the new device ready for testing and maybe kits in February/March; the prototype is hopefully waiting for me when I get back from break.