The buttons are to switch the screen off, for example. That's all. I will not have a screen, as I said, I want to get rid of the LCD PCB completely.

And sorry dude, I love what you create, but I want to make this myself.

I found these PCB schematics but I'd like something simpler, not an electronic schematic, but I'll post them here for other people's references.
http://gbdev.gg8.se/wiki/articles/DMG_Schematics

why would you want buttons? you don't have a screen?

the ones i made were made out of gameboy pockets, there is no schematic on the internet for them, you could always pay me to make you what ever you want

think about it, all the awesome things i could make for you...oooh what about this MGB thing but built into a keyboard, or keytar? or a group of them with pitch control all wired to a single arduinoboy for cords???

so many wonderful things!

Yup that is EXACTLY what I want to make. But I guess I'd have to wire some buttons. Where can I get a schematic to know which lines are the buttons? I don't mind adding buttons, I just don't want to use the LCD PCB anymore.

Thanks guys!

yep, you want to make yourself something like this:
http://nex.gg8.se/modblog/2010/04/modular-gameboy/

Its nice to be able to disable the screen on a dmg for better signal to noise and faster performance.
Thats the only thing I can think of

I was wondering if you would actually need the up-down-a-b- etc controls for using mGB or if you can use it perfectly without any sort of controls. Let's say I set up mGB the way I want and then I just want to play with it.

I have a broken game boy and I was wondering if I can put it to ues without it having the controls working well.