REI Sahara are a favorite. The new ones have full vertical zippers on the leg section, so you can take them off without going over your shoes. Nice idea, but may be too complex. The #1 complaint I see on used ones in the REI Gear Garage is broken zippers. They do make several inseam sizes too. Tend to be baggy. I see good used ones in thrift stores all the time.
Columbia Titanium are pretty close to the REI pants, with a little different finish to the fabric, baggy too.
Ex Officio is good, with several models. Some have lighter (read cooler) cloth and are less durable.
Outdoor Research Equinox convertibles don't have the thigh pockets and come in inch-increment waist sizes. Less Inspector Gadget looking, not as baggy.
The older Mountain Hardwear models had a chamois fleece liner in the waistband and crotch and the waistband was more conical. I don't know if the current models offer any of the same features. The old ones are about $100-- not something you care to shred in the brush.
RailRiders are another good brand, but no zip-offs.
I want to see pants with roll-up legs with tabs like you see on some Swiss Army-style shirts-- Ex Officio Airstrip and the like. Somehow it seems to be an effort to stop and take the bottoms off or put them back on. There are issues with the extra seams, the zippers and the possibility of losing the leg sections. Velcro tabs and elastic cuffs are on my want list too. The OR pants have drawstrings.