This one took a little over a week.
Worklog1: viewtopic.php?f=1&t=38001
Worklog2: http://forums.modretro.com/viewtopic.php?f=29&t=3420
If you want to see a lot more pictures, PLEASE be sure to check out one of the worklogs. (They're the same, just on different sites.) There are all sorts of pictures there.

Specs:
600mAh GBASP battery (Gives about 2 hours of play with the sound off)
The case is the case an iPod touch comes in.
3.5" Screen
Has joystick and paddle controls
Has a cartridge slot!
2nd Player port
A/V out port
External power supply port
Low-battery indicator (Goes off at around 3.05v)
(Here is a thread for it: http://forums.modretro.com/viewtopic.php?f=7&t=3640 )

And now, pictures.











Gut pictures from the worklogs:








Here's a video for your viewing pleasure.

sweet, good job. is that a ipod/iphone case?

Yes it is.

Make.
Video.
NOW!

This is really nice. I didn't notice at first how small it was until you added in the cart slot. Great job.

Your skills are fantastic Amazing portable that was planned out very well - the lever switch for when a cartridge is inserted is both simple and clever. The fact that you did a beautiful job with the case is icing on the top.

You gonna be sellin it?

He never sells stuff.

I still love this, Mario.

Stella...ah...she's beautiful!

I didn't realize how small that thing was

Excellent Atari build. Just wondering, any info about that screen you've got hooked up in there? Looks like a pretty small form factor and considering you're using the GBA battery, pretty decent power efficiency.

That's just really nice...

Wow I like work like this. Good job .

Slick portable there Mario.

Thanks for all the awesome comments, guys!

Bandit: There's a video at the bottom of my post.

HDC: B_M is right. Usually, if make a second portable of the same system, I'll sell one of them.

Bionicle: The screen is similar to the second one in hailrazer's 3.5" screen guide.