Had a similar problem except the bolts were so crappy the hex rounded off. I ended up getting them with needle nose vice grips but i dont think that'll do you much good. Try the heating around one bolt at a time (again) but this time once its good and hot spray the bolt with an upside down can of duster. Heat the rotor, freeze the bolt essentially. Stick the allen key in the bolt real snug and wrap on the long end of it with a hammer. If you still got no dice, do all of the above but substitute the "whack the allen key" with an honest to god impact gun.
If you manage to get them out may I suggest never-sieze.

second on the Pb Blaster just spray it and walk away for a while then give it a try if no go spray again and walk away. If that doesn't work then you will have no choice but to use heat and a bolt extractor the kind that slip over and grab tighter as you loosen it.

yeah that stuff works on everything worst that can happen is you are back to where you already are. Best that can happen is it works and you can finish your project and still have plenty of PB for future issues. I work at an auto repair shop and we use PB on all the front end and brake stuff. Spray everything down first then start taking tires off and what not by the time you get to the stuff you sprayed it all comes right off without breaking any bolts which is a good thing and when you getting paid rate its a very good thing

an impact driver works well

also, try tightening it a bit, sometimes that will break it loose.

Here's a handy tool that I used to use on frozen screws on outboard motors that had been in salt water.  I've had it in my tool box for over 40 years.  Snap On makes one too but quite a bit more expensive.

http://www.sears.com/shc/s/p_10153_12605_00947641000P

Here's a little article that explains the use of the impact driver with links to both the Craftsman and Snap On wrenches.

http://www.kk.org/cooltools/archives/000723.php

Leverage is our friend.