That sounds awesome! I don't know anything about the mixing capabilities of those TX's but I'm thinking with a bit of playing around you could get the revs to be full out with no stick movement and as soon as a hydraulic function was used have them drop off slightly. This would give it the effect of having the engine bog down when digging hard I think.
Or are the sound cards only good for idle and pinned noise? I've never had a sound unit so I don't know what I'm talking about but I know that would sound cool....