The first problem with a nitro crawler is that nitros don't crawl, they run over things. The Revo in the traxxas vid did a nice job of running over the rocks but it didn't actually crawl over them. A good crawler (like the ones we watch with wide eyes in the vids) has a top speed of around 3-5 mph. Have you ever seen a nitro put out real torque at that speed? Even if you could get it going that slow and have the torque you need, the engine and clutch would have trouble with over heating. Electric is cheaper and easier plus it has a butt load of torque at very slow speeds.
Nitro crawlers, anything is possible.....But is it really worth it?