Thanks for the link to that node, of course it was exactly what I was thinking about doing.... a Tk or Gtk2 front-end to GnuPG. The idea I had, stealing from some javascript keyboard security code, was to make a mouse-driven virtual keyboard for entering the password, to avoid keystroke loggers.

I did do some digging on ramdisks and tmpfs, and disposible swap.... and it seems that if a program is on a ramdisk, it will execute there, and can then be wiped. But many gotcha's start to creep in, like does the entire Perl executable, and it's modules, and finally the script itself, need to be on the ramdisk.

Thanks to all who answered. By the way, I agree the idea of freezing a laptop to slow it's memory drainage is a bit James Bond-ish, but the idea of root, routinely dd'ing off /dev/mem and /dev/swap to search for password strings seems a pretty plausible form of insecurity.