Once, when I was into Hi-Fi, I built quite a few OTLs. None of them sounded quite right to me.
I really like CF output. It is pain in the ass to drive the output stage, but with a good interstage transformer and 6B4 driver, it sounded very very good.
You can see some more OTL designes here:
http://www.audiodesignguide.com/otl/index.html
On ebay 6C33 is $9.95, when you buy 10, and little over $10, when you buy smaller quantities. Search for 6C33C. I remember reading high failure rate of this tube working in OTL.