after reinstalling and doing some reading I've had more success.

looks like binaries and source for all of the extras packages are available from the maemo repositories in both armel and x86 flavours.

in scratchbox I added

deb http://repository.maemo.org/extras/ bora free
deb-src http://repository.maemo.org/extras/ bora free

to /etc/apt/sources.list

then to install something (e.g. aisleriot solitaire) I ran "fakeroot apt-get install aisleriot" in scratchbox and it installed and ran without a hitch.

list of ARMEL binary extras here (there's probably a friendlier list elsewhere):
http://repository.maemo.org/extras/d...armel/Packages