I think I've seen a few of these bad boys on show in the domestic T20 competition, albeit [and inevitably] re-stickered to allow for sponsorship.
It's from Black Cat Cricket, a London maker of bespoke bats, and it's a far more intuitive response for the need for big wood in T20 than the Mongoose. The handle's longer, the blade shorter, thus keeping the weight - if not, you'd assume, the balance - pretty standard at a saucy 2lbs 8ozs [for Glamorgan last night, Mark Cosgrove had a standard bat of similar dimensions to the Joker - it weighed 3lbs 4ozs].
As for the edges - man, you could get the first few pages of Lolita onto them, and they couldn't be any ruder. You must get a little shiver looking down at those as you await the bowler. Oh yes.