I've only seen and held one of these, not lamped with one, but it's definitely on my Christmas list!
They're very light weight.
http://www.northeastfieldsports.co.uk/lamp...y-pack-151.html
Out of stock on NEF site though
Thanks for that SS, nice kit but a bit pricey and would really prefer a 14 or 17ah one, otherwise would need to buy two!! Cheers, D.