argh - the bq2419x series only provides up to 1.5A @ 5V in USB-OTG mode, not 3A. which rules it out. it's otherwise perfect, damnit. i'll have another search - bq2416x series isn't good enough as it only does 2.5A.
i'm currently updating http://rhombus-tech.net/community_ideas/laptop_15in/ to add connector specifications. PDF schematics and layout image links: http://hands.com/~lkcl/eoma/laptop_15in/laptop_15in_PCB3_rev2_1.pdf http://hands.com/~lkcl/eoma/laptop_15in/pcb3_layout.png http://hands.com/~lkcl/eoma/laptop_15in/laptop_15in_PCB2_2.pdf
l.