There is a custom 7 string CEC on ebay. It was apparently an original CEC that was modified with a wider neck and RMC pickups with eq but no individual pickup adjustment. The neck width is 2-3/8 inches. It might have some interesting possibilities if you can adjust to the wide neck and added bass string.
http://cgi.ebay.com/Gibson-Chet-Atkins- ... _500wt_929