Did a lot of searching on the interweb for this exact same kit a month or so ago with the same result. I'll be watching your thread.
Pretty pricey bit of kit so I just stopped looking. One suggestion would be to maybe call Azetch Armory directly and see if they have any specifics as to why it's "ON BACKORDER, INDEFINITELY". They looked like the only on-line site that offered it in NA(?).
Best of luck. Kit costs more than a new 10/22 carbine rifle. But...I'd still buy one. Looks to be pretty high quality.