DaveC,
There are three people that I know of who are persuing this project at this time.
As far as I know, none of them have an inventory of these, they would need to be ordered and custom built. These frames start as salvaged RE frames and most mounting tabs are removed to clean them up before adding the hard tail. You may need to replace those tabs you would chose to have. ie air box, battery carrier, fork lock, etc.
E-mail me if you would like some numbers and I will see if they wish to be contacted.
jim