Hi there...
found this on the web
"The Laparoscopic Gastric Bypass, Roux-en-Y, first performed in 1993, is regarded as one of the most difficult procedures to perform by limited access techniques, but use of this method has greatly popularized the operation, with benefits which include shortened hospital stay, reduced discomfort, shorter recovery time, less scarring, and minimal risk of incisional hernia."
The first use of the loop gastric bypass, in 1967, used a loop of small bowel for re-construction, rather than a Y-construction as is prevalent today.
So I guess there are longer term patients out there but its hard to find any detailed research.