Well, I got Ubuntu 7.10 installed on an 8 gig SDHC card and away I go…
4.5 gigs used for the base Ubuntu system as well as the base GIS software:
1) Proj4 (4.6.0) 2) GDAL/OGR (1.5.0) 3) GEOS (3.0.0) 4) Postgresql (8.2.5) 5) PostGIS (1.3.2) 6) QT dev environment (4.3.2) 7) QGIS svn (0.9.2)
What do you get? Well, an ultra portable GIS workstation weighing in at less than 2 lbs that is very fun!
http://media.reprojected.com/presentations/Videos/eee_qgis_install/eee_qgis_install.html