I set my cyclocross up with a triple front and a touring rear. The cycle shop questioned me on why I did it. I explained that the last mile was also 600 foot climb. The super fit kid working there was like "that hill is easy, I do that on my speed gears". I said "yea but look at me". He said "true". then proceeded to say he couldn't install it because shimano wouldn't recommend it (too many tooth delta). But he'd adjust it if I put it on my self. So I did. Basically it's a road front with a MTB small, and a mtb cassette in the back.

It's got 5k miles on it and works fine. Just needs little tweaks every once and a while and you can't do full crosses like Big Big. But it goes as fast and as torquey as you could please (or can buy).

These things work pretty well. Just learn to tweak em or get them tuned up.