Custom bushings

[asid61]

What are some good materials for a large custom bushing?
I was experimenting with some interesting turret ideas, however, a few of them require large custom bronze bushings (~2.625" OD, 2" ID) in order to be geometrically correct.
The turret only weighs around 30lbs, so would aluminum bronze be an okay bushing material? Do machining sponsors hate working with bronze enough to refuse or is it different from copper in that respect?
What are some other bushing materials?

Also, this is assuming that we don't just buy bushings. This is pretty theoretical right now, so I wanted some opinions on fabrication and materials of custom bushings.