a little surprised that no one mentioned about this game, perhaps it's still alpha?

http://www.pdamill.com/flux.shtml

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FLUX CHALLENGE
Alpha Demo v0.2

Flux Challenge is our upcoming 3D racing game. This unique racer revolves around a world of magnetic-levitation tunnels. While originally designed for mass transportation, it soon spawned many underground ship-racing circuits and eventually became one of the largest international championship sports. Take control of one of these magilev ships, and become the international champion!
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It plays great on my x3/x30/x5 so give it a try (a little weird on the x5 for me, for some reason i can't get used to its dpad...)

cheers,
kaz

HP ipaQ hx4705 wm5 2.01 /w AKU 3.5.2
Dell Axim x50v WM5 /w AKU 3.5.2
Dell Axim x30h wm2003se A06 JPN
HP ipaQ h6315 wm2003 TWN
4GB Transcend SD Card 150x x2
8GB Trancend CF Card 150x x2
Eng->Jap x50v tutorial