I always think the thing that lets down a bimble stove is the fuel - you have to carry a gas cylinder (expensive and you always end up carrying two when one is ready to run out) or a larger bottle or liquid fuel. In my "man bag" I use a hex cooker and crusader or a gas stove in my rucksack.
A couple of people I know have bought these
http://cgi.ebay.co.uk/RAPIJET-REFIL...ryZ16036QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
They seem to like them for day walks - 3 hr burn time, integral gas storage that you top up from a butane lighter cyclinder. Not as tiny as the optimus, but probably as small or smaller when you take fuel into account - and a lot smaller
3 1/4" by 2 1/4" 454g inc fuel.
Not a long term thing but pretty cheap to buy and run for a day walk stove
Red