I went to the post office and picked up my Freedom Keychain GPS 2000 (bought from Proporta). It's a fascinating little device (1.81 x 1.26 x 0.58") that provides NMEA 0183 and other protocols over Bluetooth. It charges via the usual Mini5B USB, which is great as it means one less cable for me to bring along. USB and cigarette lighter cables are included in the package.
To test it out, I first paired it with osgiliath (my N800/ITOS2008), installed Maemo Mapper, then went to the roofdeck of my condominium. It worked pretty well, using 8 or 9 of the 12 satellites it tracked. I texted the bros with the coordinates and altitude, along with some quip about telling Cupid exactly where I was. :-P
I haven't put it fully through its paces yet, but so far, I was able to see my location on osgiliath using maps from Google Maps and OpenStreet that Maemo Mapper automatically downloaded for me. The street maps even had the street names on them!
My ultimate goal is to geotag my photos by saving my GPS path and matching the time the pictures were taken, i.e. move the SD from my cam to the N800 and run a script. I hope there's an existing app* for this already, but if not, it would make for an interesting project.
* UPDATE: HowToUseGPSFrameworkInOS2007 should work, though it needs a PC. Not sure if it is worth the effort (or even feasible) to port gtag's requirements to the tablet itself.