Yes, that damned gap! Hahah.

I honestly think you'll be hard pressed to shave much space no matter which route you take, 4 channels takes up space, no way of getting around that. I would say the only major place you can shave some weight is in the oscillators. If you can find slimmer versions of the same components elsewhere, it might be worth considering, but honestly, I think it looks really good the way it is. You can always just buy another rack! Haha