Here are some more details to the mod:
Materials:
LCD Screen:
10.4" 4:3 from ebay (ebay user digital_r_us)
Speaker with amp: I used
this one. Any other mini speaker will also work...
Wheel potentiometer:
Radioshack 10k
Game Genie
Case hinges (preferably with a 90 degrees stop)
Ribbon cable 36-wire
In order to place the LCD controller board underneath the NES motherboard I had to desolder the expansion port.
I cut the heat sink shorter to be able to install the cover later.
On the LCD controller PCB I had to desolder the power, S-Video and composite plugs.
Power for the screen is taken from the input of the 5 VDC voltage regulator, and for the audio amp from the output.
The cartridge bay is the original one from the NES. I just trimmed it and glued it on. Same with the Game Genie.
As the speaker didn't have volume control I installed a wheel potentiometer.
That's it - not hard at all (Well, it's easy to say afterwards...)