Yes that's a good rate. The lowest quote I got was for $225 for blasting and powdercoating of just the frame.
I wouldn't worry about heat dissapation, a lot of factory calipers are powder coated (porsche anyone?). And check with your powder coater, you may not have to completely disassemble your caliper. You can powder coat at lower temps (longer cure times) that may be safe for the o-rings. I've had porsche calipers re-coated and they did not need to be taken apart.
Decals will stick to powdercoating the same, the differnce being if you decide to take them off the glue will not damage the powdercoat. And you can use a solvent to dissolve the glue with much less risk of damage to the paint.
I haven't looked at my 750's handlebar switches just yet (are they even metal???). If they are metal, they should be no problem to powder coat. If you scuff the area where you want the red paint it should stick with no problem. But if you are having them powdercoated, why not have the lettters powdercoated red? It's possilbe to powder coat in different colors on the same piece.
I have a small (can't do the frame) blasting\powder coating setup in my workshop and love it. I might try and powdercoat the whole bike rather than paint it!!!
Good luck,
Matt