no, but i would rattle can a bike frame. and have done several times.
ever heard of a thing called job satisfaction? everytime you look at your frame you can think - 'i did that, it looks well good' or you can think ' the powdercoaters/professionals did that because i didn't think i was good enough to do it myself'
the long and short of it is that you can get a good finish with rattle cans if done properly, and the paint job can involve more than one colour.
as for it taking 3 days, thats a bit of an over-exaggeration, unless you watch the paint dry...
each to their own i suppose, and i can see the benefits of a powder coat!