The antenna at ventantenna.com is an H.F. to 6 meter portable.
The site is inaccessible but if interested the reviews at
http://www.eham.net
give one a pretty good idea of how it goes. Pretty good reviews too.
Can also be setup for 2 meters with home made radials.
I havn't found anything about V/Uhf vent antennas yet.
Tom Fowle WA6IVG