I made one. Cut an extension in 1/2 and welded a piece of 3ft bar stock to both ends. I can't remember now what I needed it for, but it worked.
I bought a set from HF with a few 3/8" and a few 1/4" that were at least 2 feet long and for the very little I have used them they have done fine. They were only like $10 to.
Cornwell makes a 2 foot one. I've never seen a longer one.
http://www.cornwelltools.com/webcat/products.php?product=E024-%252d-1{47}4%22-x-24%22-Extension#
I have a set of MAC locking 1/4 extensions, the longest is 24". When extensions get that long, they need to be real good quality to hold up.
Charles

Interesting. Wish I were a better welder.
How is it any different from a short one?![]()
Why not use two 12" extensions? Have a locking extension for the one connected to the ratchet so the second one doesn't come off.
So what is the specific use? Just curious.
I have a Williams M-124. The shaft is a bit more stout than any other 1/4" drive extensions I have: +/-3/8" versus +/-5/16" on my shorter SKs.
Um...what's gonna go on the end of the extension?Tight quarters. The joint in the center would be an issue.
Um...what's gonna go on the end of the extension?