I should think that they would be easy enough to have turned from Oilite bronze stock by any high school machine shop student for the price of a pizza. I have wondered about using needle roller bearing myself. IIRC Suzuki's GS (ca. 1978) was the first mass produced street bike to have needle rollers in the swinging arm. Oh what a superb machine.
IMHO Mcmaster Carr is a top notch company to deal with.
Can anybody confirm if the bronze bush will need grease for lubrication and if yes, how can that be done? Is it by putting a nipple grease feed on the shaft bolt?
Of COURSE the bush will need lubrication! gun-drilling the shaft bolt - and knurling it for grease distribution would be a good thing - but you COULD add a couple of grease fittings to the pivot lugs on the swing arm as well and keep the bolt solid.
Scooterbob has it wright, I'm planing on doing the latter, If I can get some internally groved bushings.
I'm guessing that you'd want to braze weld a couple of lugs on the swingarm to have something to screw your grease fittings into ..... you COULD even get uber clever and plumb them together and make one easy-to-reach fitting ...... Hmmmmmm .......