In reply to d_b:
I have a petzl glacier literide. 50cm, 316g. Is good, can get it for about £60 now as it's not very new. However, if I was getting it again I'd consider getting a petzl ride (45cm, 250g) or gully (45cm, 280g, actually seems very good for climbing), which they annoyingly brought out one year after I bought the literide. Well I'd get the gully because I'd want it to be good for climbing, but the ride would be good for walking.
I'm of the opinion that a long axe is pretty pointless for walking, but if you like a long axe then those are obviously quite short options.
If you're looking for something seriously light that just fulfils the criteria of being an axe then some of the ski mo ones are very light these days. E.g. the camp corsa race is 50cm and 188g!