My first recommendation would be the Feisol 3441T or 3442. Great tripod, very light, very stable, tall, and folds down small. Perfect for hiking. Just one caveat, it will cost you more than $500 for the legs and head. The legs cost around $400. If that is too much for you, then you can skip the quoted text, it is an example of how I've abused mine in all sorts of ways:
Took it to Iceland and used it on sharp volcanic rocks in the rain, it was partially submerged in freezing salt water (unintentionally by a rogue wave as well as intentionally at Jokulsarlon), in sand (which thanks to the wave also got everywhere), under the hot shower back at the hostel with me to wash out the salt and sand.
Took it to Scotland where it was used on wet grass and mud.
Took it to China where it was scraped along granite rocks and used in relatively strong winds hiking around the Yellow Mountains (I was extremely thankful for the light weight there, have you ever walked up and down steep stairs for 6 hours straight with a loaded pack?).
Back here in Hong Kong it has been used on very uneven rocks, and has fallen into a river twice, being completely submerged as well as being bashed against rocks (both my ballhead and the legs bear the scars).
In France it was used in a snowstorm as well as being buried in the stuff.
All in all, I don't see how a more expensive tripod would have fared any better (I do not have a single failed shot which was due to the tripod in any of those conditions, all blurry shots were a result of me bumping against the tripod or camera during the exposure, and the tripod has been so easy to use as well).
Since then I have also taken it to the Swiss Alps where it was used in the rain and mud at mid-high altitudes and the south of France in sand and salt water.
Most recently, I took it to Cambodia where I was carrying it around for many hours at a time in hot weather, bashing it around in the back of tuktuks, and getting it covered in fine dust.
My next recommendation would be something along the lines of a Benro C2680, or the equivalent Induro/Sirui.
I've played around with quite a few Benro tripods, I find they are brilliant value for money. But they are not as good as Feisol's higher end legs. They are heavier, shorter, not quite as solid, not quite as smooth to operate, and don't use materials of as high a quality.
BUT: upgrade the head. I don't like Benro heads (though this is just my opinion). I find them awkward to use. Get something from RRS, Markins, Acratech, or Induro (cheaper but still very good from what I hear).
As for flip locks vs twist locks, all the high end tripods use twist locks, not much choice there unfortunately. If you want flip locks, Cullmann and Manfrotto are the only ones I know of that make decent tripods and use them.
