I was going to post a topic on this in Modern Gaming but decided this is more of a find so here it is.
Anyway, I dropped by a GS where a friend of mine works and noticed they had a shrink wrapped Patapon 2 on their back counter. I glanced at it and noticed that the packaging was "off" from what I remember so I asked if I could see it. He hands it to me and I notice on the insert there's no mention of a download card so I shake the case a little bit.
My buddy is perplexed by my actions and semi-sarcastically says "Checking to make sure the voucher is in there?" to which I reply "No dude, I think there's a UMD in there." I peer into the side of the case and it looks like a sliver of white. I hand the case to him to and he sees it as well. We crack it open and sure enough, there's a Patapon UMD in the case instead of a voucher card.
I say to him "ring it up!" expecting it to come up at the $19.99 price point and he points out it's only $9.99.
I don't know how long they've had a UMD version available here in the states but it's nice to not have to import a EU copy or settle for the voucher. I'm assuming they put out the UMD version around the same time Fat Princess and Pixel Junk Monsters were released.