More in the front than the back makes sense to me, I'm another 160/120 Hemlock and it works superbly, very balanced. The 2 ends do a different job so no reason not to really. But it does seem to confuse people- I think part of the reason it's not more common is that people just expect it to be the same and think anything else is weird.
After all, my hardtail has 140mm more travel in the front than the back and that works fine- my legs still have more travel than my forks.
I think with more rear travel, you sometimes end up with a big bike, with all the strength and packaging of the longer travel, plus extra bits and bobs to make it pedal well, which can mean it doesn't soak hits as well as it might- you end up with the pedalling character of a shorter travel bike but also the suspension performance of a shorter travel bike too, and extra weight and cost for all the linkages and such. And at that point why not just be a shorter travel bike?