I just did a google for Blue Jay Kits and didn't notice anything saying back order but it's worth a phone call to them. You can go to the site and look at there offerings to see what there planes look like and the prices. I just finished there Dirty Birdy. These are all older designs and they are builders kits. There are none of the photos like a GP or SIG kit to help you along, the instructions are all just printed sheets. You can also go into the classic pattern forum and post up there.
I have built a few of the old school pattern planes from just plans I have gotten from MAN plans service. Cutting your own pattern plane kit is easy.