Did a little Google search and found this guy: Link RemovedThat actually provides center positive instead of center negative, just tried it on my cheapest pedal. Also tried the 9V battery snap connector that comes with the Voodoo Lab Pedal Power supplies and they're also backwards. So you would need to use something like the adapter you linked to, but with a reverse polarity adapter. I'd rather have a single cable with a 2-3" cable. The OneSpot linked would be perfect, if the polarity was correct.
Looks like the ticket!