well, once you make the n900's usb controller to think he is the host (by using the force_host option, if it works on omap3430/twl4030), you only need to use a special cable (and probably inject cutom power source too)...

it's all only about setting up of the host-client session on data bus (which should be very much only a software problem - I've read somewhere, that for a long time now, most (even the simplest) embedded client usb controllers support at least a primitive host mode)...)

the only obsticle I can see is that either the hardware is horifically badly designed (like it can't be a host, because of some electrical out-of-usb-spec issues when connecting other device.. i think there were some problems with host mode on otg port of BeagleBoard too (with older revisions), so it could be something similar) - or omap3430 doesn't implement the force_host (correctly)...

please, Siggen, post the answer(s) here again, if you get some...