Good news is that white is perfect to paint over. But that shape would be hard for an amateur to cover properly without runs and drips. Painted portions of cars - door, fenders and quarter panel but nothing that round.
Maybe a local technical college auto body class could paint it for you cheap (or free).
You may have a point there with the thing being as round as it is.
A friend had one painted for 400 but had to break it done for painting. I shop around and see what shop's are getting for this kind of job.
Not directly to your question but if you want to take a trip, I had these guys paint a set of hard bags for me a couple years ago. They perfectly matched the two tone colors and pin stripping of my Valkyrie standard (red/white) and the finish was fantastic. Oh yeah, a really good price. Talk to Mike or Shelby, use my name.