5th cell... has anyone seen this?

[merc]

I found this guy trying to sell this xmod with 5 cells. This is what he wrote:

"A holder for a fifth AAA battery. These were made to use 4 AAA batteries. If you use standard 1.5volt non-rechargeables that is 6volts. If you use NiCd or NIMH at only 1.2volt per cell you end up with only 4.8v. This modification will let you add a fifth nicd or nimh cell to get a full 6Volts! This has not been tested with 5 alkalines which would give a whopping 7.5v, you can try that at your own risk for even more speed."

I was wondering if anyone else here has seen anything else like this or has tried it.