I recently read through all 13 issues. I tells ya, if they'd re-release those in a manga-like digest size, they'd move TRUCKLOADS of them. Hell, I'd RE-BUY them, and I HATE re-buying stuff!
Kaja said that they would be contacting all subscribers about ways of compensating them. I'm a little surprised you haven't heard from them yet. But only a little. They have a small and very busy staff.
Ah... from the mailing list: "Girl Genius subscriber letters will be sent soon, outlining compensation for unshipped issues. If your address has changed since December 2004, or is about to change, please let us know at your earliest convenience by sending email to customerservice@studiofoglio.com confirming the old address, & informing us of the new one. Most excellent. "