Right. I recovered another bricked WR703N, this one looked intact but just wouldn't boot, it needed a console connection and once that was soldered on i could boot it into maintenance mode and flash a working image.
Below is a picture of the brains in its current state. I've added a five pin header of which rx/tx and gnd are now connected. Put the header on top of the USB host connector and broke part of the casing so it's accesible when the casing is closed. For now i'll leave the board in the casing, the pads on the board are pretty fragile and this way i don't have to worry too much about tearing them off.
The two extra pins are to be used for the I2C interface. I have yet to solder those to the board. Right now i'm compiling an openwrt image with i2c and python. Never compiled openwrt from scratch before, i'd like to have a booting, self compiled, openwrt before i start on the extra mods.
The I2C part should not be too difficult, i've got some proven I2C slave code for an atmega88 from a previous project. I'll clean up that code and put it on Github. As soon as i have control over a microcontroller from the router i'll start building a mobile platform. We recently acquired a shitload of Technic Lego at my local Hackerspace (Hack42) and i'm thinking i could use that to build a prototype vehicle for further development of modules and software.