Epic aside, no. Not a good idea, this is one of the special focal points of balance we're not supposted to touch... The main idea being that you need to remain close enugh so that the target can get to you with a standard move.
My problem with this is that you can't hit a collossal red-dragon's collossal vitals any farther away then you can the tiny vitals of a tiny grig. For a while I had a house rule to change this, but it's really more troubble than it's worth, so I abandon it.