In regards to the Original Poster's question, I think that the Bell's are generally pretty busy with their real lives, but have always gotten to people in turn. Clearly, if you need something right away, the Frazier or API wheels are readily available. I have been quite happy with my API for a couple of years now - no complaints. It did take and hour or two to install, as I had to drill it to the tailwheel spring. Louise got a bell wheel late last year, and it took a few minutes to install, as it just bolts in. It (and I assume the Frazier, if it has the same shaft diameter as Van's) also can use the Silver Bullet control arm - mine can't as the shaft size is different. Trivial, but a difference....
Buy whichever of the three you can get on your schedule - but buy SOMETHING other than Van's....
Paul