Max,
If nothing else presents it's self, you might try a
'CCD' (Controled Capacitance Distribution antenna). The
biggest draw backs are that they are a wave length long
and use silver mica capacitors that are not cheap. But
it can be laid on the ground and they do work. There's
a pretty good writeup in one of the ARRL's Antenna
Compendium books, not sure which one. It wouldn't be my
first choice in your situation, but it is an alternative.
'Doc