I like your setup. If I decide to mount mine in the engine, I may go that route.
That said, the space under the hood looks pretty limited. Where you have your compressor mounted is one of the very few free spaces in the engine compartment, and a spot I've seen others (Dissent Offroad) use for their switchpro mount. I was thinking of going that route. That, and I think a compressor somewhere in the back may be more handy for me.
Thinking about mounting it in the jack position a little more, I know there's a factory Lexus GX550 accessory that would mount a compressor in the compartment where the battery is on the 250. So, apparently Toyota isn't too concerned about heat (unless they have a special compressor that runs cooler).