On the Ofna MBX I have a AE battery holders which proabably does hold heat. I had not though about that. It might be worth changing that. On the Losi, I was planning a flat piece of Aluminum with velcro and also a Gorilla strap.

I have also though about Quark and 5s and maybe a Neu motor, but I have not heard much about setups like that and how hot/cool they run.