As you probably know already, I use monopods a lot, often as quick and portable alternative to tripods. My favourite lightweight tripod is the Velbon UltraStick R50 monopod. It’s super lightweight, portable and it has one of the most ingenious locking systems I’ve seen.
I’ve been using it for nearly 2 years now and definitely feel that’s it’s also going to hold up against the abuse of a travel tripod.
Velbon also make a lighter version called the UltraStick L50, which is also a great alternative as it’s also cheaper.