Upcoming action/gore title MadWorld will run in 480i as opposed to 480p.
According to IGN's Matt Casamassina, the game will be running in 480i, instead of the Wii's maximum output of 480p.
Usually, lack of 480p support can be credited to developer laziness. No way such a claim can be leveled at Platinum Games or MadWorld... I'm wondering, then, if the studio simply wasn't aware that 480p is 'kind of a big deal' for a chunk of Wii owners.
480i and 480p both output at the same resolution, but in i only 240 of the 480 resolution lines are viewed at one time, where as in 480p you'll be seeing all 480 at one time, which should provide the best possible picture for Wii games.
Thanks to Kotaku, C3 Reader Marzy for the tip.