McMaster-Carr has a 1-1/8", extra-deep socket, 1/2" drive, with an overall length a tad over 6" in their catalog. Their url is
http://www.mcmaster.com/
The socket is in stock, part no. 55375A43. It's listed at $37.14. Also, it's a 6point, but I'm guessing you have enough swing room for that to be a non-issue.
You could probably find something similar from just about any industrial tool supplier, this is just the one I'm most familiar with.
Good luck.