All good suggestions. No one has mentioned Reeves 2000- very fast dispatch. Another good plan is to befriend a CNC shop. The "Multibore" collets modern lathes use cannot grip anything shorter than 2-3" long, so consequently lots of bar ends go straight in the scrap bin. Any jobbing workshop will hold a variety of stock, and all my local ones would always sell me metal if I asked nicely, or put me on to someone they knew would.
-Andrew UK