Luckily i do have an ultra-lightweight tripod which I used when i first started filming, and like you said with a removable plate! However, my larger Velbon tripod ( DV-7000 ? ) also has this removable plate.
I've planned two ways; one which im cracking on with now, which is literally just selotaped down, and I'm looking at ways to improve that now, and will post a picture shortly!
Other way is like you said, but I cant find the our stash of Sat Navs to steal the suction cups, so that can wait until later!
FS