One nice thing about a radiant heat panel ("RHP", which is not the same thing as a 'deep heat projector') is that they can be installed so that it is very difficult for the snake to contact it in any real way. They're flat, and are attached underneath the top of the enclosure, so a snake would have to telescope up and hold itself against the ceiling to contact it.
Whatever you end up using for the heat element, don't skimp on the thermostat. I strongly recommend Herpstats.