Here is one example which came up on a google search...

http://www.arizonatools.com/catalog/browse/3586-3595-3616/detail/17257/

However, I to not think that is technically a drift... and probably that you did not intend to specify drift as compared to a punch...
I am a mind reader .... a drift is a tool with a long taper and used to catch the edge of a hole not ligned up with another.. then you drive it in to bring the two pieces in alighment long enough to put a bolt or rivet into the hole..

However, It would just kill me to pay that for such a piece of metal like that..

I bought a 20 FOOT 5/8ths rod of brass not long ago for less than $20.... just get out your yellow pages and look locally for ' metals' wholesale.

Remember, Cheap is better.... or gather up some names of others, get the long piece and cut the long piece up and send it to others who will be needing it in the future