Kawmeister and I were talking about this yesterday - he said Kelowna Electroplating used to have some guidelines on their homepage which gave some instructions on what preparations you could make yourself to the parts you wanted chromed in order to make the process as inexpensive and efficient as possible... I was just there and those instructions do not appear to me to be there now. I guess this commerce begins on the phone, but Kawmeister's recollections of what was there were fairly extensive, and included, amongst other things, you building special shipping containers and photos of your parts packed away in them, if you were going to be super-demanding about how things were shipped, for example, which makes good sense.
I have used them for car parts in the past - bumpers, over-riders, and taillight bezels - and what I remember is that it was fairly expensive, that if the parts were not in really nice shape going out, they were (surprise) somewhat over-polished (loss of crisp lines in polishing, for example, resulting in soft-looking contours) when they came back, and if the part had holes that needed to be filled, the filled area was still visible to the eye afterwards, in spite of the work they did to hide it.
Another thread said there was a place in Burnaby that was supposed to be good quality work, but I know less than nothing about them. As Hans was recently reminded, nothing like being clear about the expectations and costs up front to avoid unpleasant surprises; I imagine phoning them would be the only way to assure yourself the entire process was workable, and the costs justified.