I don't know if you've already looked, but try PMing Ronime - THG Props. He sells completed E-11s and told me he's currently creating a new batch. You could also try looking for a DLT-20A It's larger but I actually got one for relatively cheap (and it's metal to boot)- however you'll probably have to do some searching to find one.
His thread
http://www.whitearmor.net/forum/topic/24500-thg-props-v3-rubber-anh-e-11-blasters/