Sorry, I should have said, I'm going to be doing a lot more landscape photography in 2013 onwards, but I'd like something relatively light and compact as I'll be hiking with it.
Thanks for the recommendations D.P. I'll check them out.
The other requirement is that I must be able to buy it in Canada. I haven't got a massive luggage allowance so the more stuff I can buy when I get there rather than lug it out there with me, the better.
Most of my suggestions are on the heavier side but I use a BH-55 for hiking 12-14 miles, 3000-4000 feet with a 300mm f/4.0. Tiring but doable, depending on your fitness etc. If I want to go light I tend to go for a monopod, even tempted at getting one of the those telescopic hiking poles that have the 1/4" stud to mount on the camera base. And recently I purchased a small m43 camera for when I really want to be light, I do some Skimo (ski mountaineering racing) and like to go really fast and light at times, I have spent thousands getting super light skis,boost, avy gear, clothes, backpacks, I even modify my ski boots cutting off straps, drilling holes, I cut off useless straps form my backpack etc. So when I go light, I really go light, otherwise I tend to ignore weight and take the full tripod.
The Acratech heads are about 450g and lighter than the other I suggested. Really right Stuff also offer a smaller light, BH-40 which is very, there is also BH-30 but this is probably too small to be useful.
If weight is a concern you can look at other places to save weight. Many backpacks weigh in close to 2kg, but you can get backpack that is just as function at 1.2-1.3kg, and backpacks that are almost as function in the 800-900g range. Changing a Nalgene bottle to a used 2l coke bottle saves to several hundred grams. Some winter jacks weigh well over 1.5kgs, but you can gore-tex pro shell in a little over 500g and a spend pack a polartec micro fleece for a 250-300g, you will be more comfortable and will have saved a load of weight.