Regarding powder coating,
When I was cash strapped in the 80's I had one coated, looked good, turnaround was fast so time between beadblasting and recoat was short, so no rust developed prior to coating. The finish failed quickly primarily due to the thin flowing of the film as it is in its semi-liquid state, it pulls thin at sharp edges, temp can be reduced sometimes, thickness increased but it is hard to get around the physics.
I have also purchased two other bikes that were powdercoated, upon stripping via chemical process, rust was visible under both even in areas not showing any problems from above. None of the powder finished performed significantly more durable than a good paint job, but were all more work to remove.
The verdict for me, on Aluminum or Ti, acceptable, perhaps on a fillet brazed frame (less braze-ons the better) but not on a lugged steel frame.
The price quoted in Peter N's postings does not seem too far away from a quality PPG or Imron job.
As the air quality standards get tighter it may be the future, but not yet for me.
John Jorgensen
Palos Verdes Ca