The GRASS module r.external has just been added to QGIS: I think this is
a major addition, as now it is possible to link to a raster in its
original format, without importing it, and make it available for all
GRASS analyses: it saves a lot os space and time.
You will need grass64 and q fresh QGIS (but you can also take the module
from svn and copy it to the appropriate place).
Feedback welcome.
All the best.
--
Paolo Cavallini: http://www.faunalia.it/pc