I found some non-sealed type bearings that are much cheaper. Less than 30 bucks, iirc. Much easier to clean/re-grease. They are 32203 bearings. 17x17.25x40 mm size, tapered roller.
With a machined spacer, you could use 30203 bearings (notice there is only one "2"), which are for the wheels and older swingarms for airheads. They are 17x13.25x40 mm. The spacer would be a 17mm ID, Width (height) of 4mm.
Snowbum prefers the non-sealed type on his airheads for easier, more frequent greasing.
The bearings seem fine for street use. Maybe even overkill. They provide extremely rigidity, without significant drag or wear: something that bushings can't do. There is no slop in a bmw swingarm.