I just placed an ERDAS export filter on an anonymous ftp site here.
It will place multiple raster layers in a LAN file.
It is available at ftp://blue.lakeheadu.ca/pub/grass/i.out.erdas.001.tgz
for the source code, or i.out.erdas.zip for a linux binary that works
with kang's release of GRASS for linux.
It is not yet on moon because it still needs some work, but it works as
far as I can tell.
Good Luck!
Angus Carr.