On the same yet slightly sub-topic'd
peripherals-wise...
currently I use a stereophonic pickup perfect for the low and high ends of the soundbox somewhat similar to this...
http://www.ebay.ca/itm/Schatten-CH-3...item54155527fc

Mine is much more expensive and isn't as invasive than that one...and I input-it into the mic port on one of my toshiba portege m780's (convertible laptop tablet with stylus and finger touchscreen) on which (I now have changed favourite distros for music creation to....) I'm using antiX 15 x64 with rakarrack ..(and now) gtkgep (and a few other programs as well) manipulate sound on-the-fly-while-playing and then output the processed sound live to either my headphones or a couple of amps...

Don't need fancy expensive pickups...
I also have a few oysters that are more than fine for the job...producing good quality sound...you can get away with any of these numbers..
http://www.ebay.ca/itm/SOHO-ACOUSTIC...item2a27cd13dd
http://www.ebay.ca/itm/Schaller-721-...item3f4df1e1f3
http://www.ebay.ca/itm/SCHALLER-723-...item339c6ee994
(In fact I have a couple Schaller oyster pickups..
they haven't changed their look either...
I've had mine since I was 20...more than 25 years ago now...
and they still work like new.. good durable workmanship in Schaller...
And then just about any musical instrument can be amplified...from harps, lutes, violins, guitars right on down to the tone box and kalimba ....
So it really does allow for virtually anyone to pick up a musical instrument and electrify it. )

add a couple cheap gold-plated 1/8to1/4 or 1/4to1/8 male to female..female to male ..male to male...whatever you need frankly to connect from and to...and they are stupid cheap ..under $5 each...

I imagine this (below) would work adequately for gtkgep for the n900...and I wonder if the 770 and n8x0's could also utilize this plugged into the headphone jack on 770 / n8x0 device and outputting via mic adapter out to the end-users choice of pickup and the headphone adapter out to the end-users choice into headphones...or into computer for whatever additional work and then outing from computer into headphones or amp(s) ...or simply out to amp(s).
http://www.ebay.ca/itm/3-5mm-Stereo-...item56700481fd