Something I think should be in here is some info on the aerosol can spray-on bedliner. Some folks do small stuff with it, like parts that need a more durable coat, and I've seen tanks, tails, and wheels done in the stuff. On my bike I've got the kick lever, shifter, fork legs(they were pitted and the rough texture covered that nicely), headlight bucket(for texture), blinkers (pitted slightly), my starter cover, my license plate bracket, and other things I'm forgetting.
As far as brands go the only two that I have experience with are plasticote spray on bedliner and rustoleum spray on bedliner. The plasticote will give you a firm, very rough textured coat. The rustoleum gives a smoother softer black, it also appears to be the more durable, but it doesn't quite have that rough tough bedliner look.
When you get ready to apply the bedliner the first thing you need to do is to prep the object for the spray. If you haven't properly prepped what you're spraying the bedliner will flake off in the near future. I usually take a wire wheel to the part first, ridding it of all rust, paint, etc. If the part is chrome I usually rough it up pretty good, but I don't spend the time to remove all of the chrome. I'm sure it's preferable to do this, but I haven't had problems painting the bedliner over chrome if it's roughed up really well. After this you clean the part thoroughly and suspend it somehow to spray it. I usually hang the parts with wire tied to my garage door and spray outward. With the plasticote it's good to spray on a light coat, then a slightly heavier coat, then wait until that coat starts to tack and do one more pretty good coat. When doing these coats you'll want to be somewhere between 12 and 18 inches away from the part using the same strokes you use when spray painting. After this last coat starts to tack, spray a lighter coat from about 20 to 30 inches back. This throws the rougher texture onto the part and gives it the tough look. The rustoleum is applied the same way, it just doesn't get as rough as the plasticote does. It's advantage though, is that it has some give. I believe that if you laid it on real thick it would self-heal from scratches, gouges and such. I always give the parts about 24 hours before I'll handle them. If the humidity is high it might take longer.
Now about taping a spot off and spraying bedliner: That sucks. The bedliner doesn't like to be taped. When you do tape it and paint it, make sure you either get the tape off very quickly or try to run an exacto down the tape line before or while pulling it (that would be pretty ballsy as you could easily scratch the surface under the bedliner). Normally after I tape things off for bedliner, I have to go back with a fine brush and clean up the lines. I just spray the bedliner onto a sheet of paper and dip the paint brush in that. The brush will be pretty fucked after this but can clean it some after it's dry and use it for this kind of thing again.
That concludes my knowledge on this subject, but hopefully it'll help someone. If anybody has anything to add, please do, like experience with other brands(I hear duracoat makes a fine bedliner), different techniques, questions that aren't covered, anything. I think this thread is a great place for folks to come and learn as much as possible. It could turn into a huge collective of knowledge on paint techniques you can pull off in your garage for very little money. And very little money is nice!