So, finally, here it is, OpenTTD for Dingoo. Sorry for it taking so long.
So, version 1.0:http://dl.openhandhelds.org/cgi-bin/dingoo.cgi?0,0,0,0,29,482
It is a port from OpenTTD version 1.0.5. OpenGFX is included, but there is neither music nor sounds. I don't like them. Copying OpenSFX into the game directory should work though.
It renders a 640x480 picture and then downscales it via linear interpolation to 320x240. This allows more things to be seen at once than 320x240 version, which is quite unplayable.
It is not as fun as it could be, because controlling the mouse with a d-pad is quite slow, but it is playable.
If you set up an internet connection for dingoo, then in-game content downloading should work too, but I can't test that now.
Also, the Options screen is too big and can't be seen as a whole, so I suggest using the openttd.cfg file directly to change options.
I hope that the next version will have better fonts, will work on that.
D-PAD : Move mouse
B : Left click
A : Right click
Y : Speed up mouse movement
X : Scroll map (hold and move D-PAD)
Right shoulder : Close all game windows
Left shoulder : Shift (speed up map scrolling, get cost estimates instead of actual building)
SELECT: Cancel current tool
START: Pause, unpause the game
You can try changing font sizes in the openttd.cfg, or using a different font entirely. After some trying I think that these settings are good, but of course you may come up with better ones.