Re: [ANNOUNCE] Open Gamepad for N900, 3D Printable
 

either you had scaling problem, or model is totally wrong.

Re: [ANNOUNCE] Open Gamepad for N900, 3D Printable
 

The n900 fits and the holes match the keyboard buttons the problem is that it's too tall in the Z axis so it moves up and down. Also, even though the keyboard buttons match the gamepad buttons, the usb and headphone jack don't so I'm suspecting it's a problem with the model itself. I didn't do any sort of scaling when I printed it out.

Re: [ANNOUNCE] Open Gamepad for N900, 3D Printable
 

Didn't the OP say he had the larger mugen back cover?

Re: [ANNOUNCE] Open Gamepad for N900, 3D Printable
 

The current model is sized to a Mugen cover. The button alignment is off as is the sizing even for a mugen cover, too tight if I remember correctly.
I have not had a whole day to sit and measure-edit-print-test from the last design I posted here which is not 100% correct.
It is easy enough to edit for the standard cover with openscad, just be sure to include a recess for the camera bump.
As for audio/USB the holes were an afterthought and I never really spent much time mathing them out. The idea for the next design is horn like gripping fingers rather than boxing in the N900.
You can also see the plastic buttons need to be downsized to not stick.