I did that ealier in the thread (naah was another one but similar thematics) but soon relaized it has a major drawback. By having them all soldered to a switch it would be a pain in the **** to change batteres by unscrewing tailcaps with those pressure switches mounted... with time the wires can break by excessive twisting...
From the look of them, they replace the existing switch assembly but keep the original tailcap and ought to be free to rotate inside the tailcap so with luck they won't twist the power cable. Not having seen one of these things other than in pictures I can't be definite about this.
I like the last one ...it has that deal or no deal look to it .