Hi,
I've updated my v.out.ascii.db script to support SQL queries.
The module "Exports vector point data with selected DB attributes"
i.e. it allows 'v.in.ascii columns=' in reverse.
Normal v.out.ascii only outputs coordinates and cat number.
Available from the GRASS Wiki add-ons page:
http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassAddOns
enjoy,
Hamish