[GRASSLIST:2773] Raster overlaying

Hello,
Would there be any way to display layers of rasters and/or vector areas on top
of a given background, in a semi-transparent way ? The d.rast -o option works
in an all/nothing transparency. Same thing with d.vect.xxx. Are there nay
plan to implement such a feature ? Did anybody write a script that would
automatize the creation of such a picture in GIMP, for example (like
exporting each layer, with the same dimensions, as a series of pictures ?)
Thanks for any help/suggestion
P.

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Soil & Water Laboratory
Dept. of Biological & Environmental Engineering
Cornell University
ITHACA, NY 14853
Tel: (607)255.2463