the first thing that i must should to say is great work to anyone has made his own portable and the others are working on their own ones.
i also must say thx to ben for create this great site.
also thx for gannon and jordin_j@hotmail.com who helped me to enable my locked accoun´t (confirmation email never arrived for me ^^)
oh well about my "project"
i built an "ugly box"

my "ugly box" have
a 640x480 lcd screen it runs on 12 v (xenarc 800m more info here http://www.xenarc.com/product/800m.html)
a modified game cube, it have qoob pro and it can read vervatim +r
it can load "backups" and homebrew stuff like gc-linux for play media files like avi, mp3.... it also have snes emulators,gboy...
it have a 12v batery (yes, all stuff is working on 12v i think it is more easy) the batery is a here
it have 12v / 10 amperes and i also get from batery case the batery life indicator. (green led when all is ok and red led when .....

it also have diferent voltages outputs like 1.5v ,3v ,4´5v,6v,9v and 12v for connect any low amp device.
i also built a car adaptor for feed the system without lose battery levels from the system.
i also upgreaded the mono speakers from the portable tv to a stereo (the tv had mono sound before fix :S ) with better cuality and i also aded a headphones-in connector, the entire system have also two fuses.
and it still have all original gc outputs like digital and analigic video conectors and power in conector.
it also have an usb conector for program the qoob stuff with new bios,programs, tools, backgrounds.....
but the project isn´t really good..., it also have some ugly things like, the screen doesn´t support games in 60hz mode, the batery only get arround 1:25 minutes of life. no controller integrated in box, yes it still need a standard one conected in the controller ports. it is very heavy and ugly, and the people think that i´m crazy or/and the portable is a bomb and i´m a terrorist...
i don´t think this is a "portable" i will better say it is a mobile gc station. ^^
at least i can play metroid prime in the bus with good image and sound quality

you can see a few photos here (srry for quality, because i made them fast)