So after trolling around YouTube and seeing especially this guy: http://www.youtube.com/watch?v=odnnxVVXJos, I realized that game music has a lot of ragtime and similar music. SO I wonder if people can come up with a list... (I know many of these aren't the official names) (Also, what is and isn't ragtime is a bit subjective occasionally so I added some close but not quites at the bottom)
For starters:

Dragon Quest V: Casino
Final Fantasy VI: Spinach Rag
Final Fantasy VIII: Slide Show, Part 2
Final Fantasy IX: Sleepy Town Treno
The Incredible Machine 3: Ragtime (may be unoriginal)
Mario Kart  64/DS - Yoshi Valley / Moo Moo Farm
Super Mario Bros. 2/USA: Overworld
Super Mario Land: Overworld
Super Mario World: Athletic
Super Mario World 2: Athletic

Similar, but probably not quite (perhaps more like novelty piano)

Dragon Quest IV/VIII: Fun Casino
Earthbound:  Drugstore (Humoresque of a Little Dog)
Super Mario Bros. 3: Second Overworld

Any more suggestions? I know I'm totallty forgetting a lot of good ones....

wasnt there a casino theme in lufia 2 that was ragtime (cant recall the track name offhand)?
as much as i really dont like that style of music,, when I can see a live piano player's hands performing it, it makes it much more interesting

edit: just from viewing that video you linked,, i found this guy who does VGM on ACCOUSTIC, FINGERPICKED guitar. and not just the lead melodies, he nails 3-4 instruments worth of voicings all at once. http://www.youtube.com/user/lonlonjp he's got some amazing chrono cross tracks

I thought I knew many ragtime VGM pieces, but it appears most of them are closer to jazz than definite ragtime. Here's one that is also ambiguous, yet it should be close to the style you're looking for.

Chris Sawyer's Locomotion - Get Me To Gladstone Bay
http://www.sendspace.com/file/hntfs9

Yeah, that one fits (as does the Lufia 2 one). There's also apparently one in Transport Tycoon.

The game with the ultimate Ragtime music.

Jimmy White's 2 Cueball

Music composed by Scott Joplin, the king of ragtime:)