http://www.milisupply.com/trousers.htm

New SAS Windproof DPM Camouflage Trousers (Ventile) are available for £60.

Probably not what your looking for being British DPM Camo.

Unfortunately West-Winds.co.uk doesn't appear to trading anymore and Ventile clothing appears to be becoming even more rare and difficult to find.

I had recently purchased a Ventile Shirt from them for around £65 ($100 USD) on sale which normally retailed for £110. I now wished I had purchased another one!

Other suppliers for Ventile Trouser both single and double layer Ventile

http://www.hilltrek.co.uk/acatalog/copy_of_Cabrach_Ventile_Trousers.html

http://www.countryinnovation.com/clothing/trousers/kestrel-trousers.html#.UXa_2j5Ft1g

A clothing manufacturer's claim of durability should not be taken as anything but marketing rhetoric. Duluth's Fire Hose pants may be great and very durable for cotton pants, but I seriously doubt they come close to the durability of nylon. Wander through the RailRiders website and you'll find they refer to their line as the "Toughest Clothes on the Planet". Is that true? Maybe, maybe not -- but they're probably tougher than most of the cotton. Just my $.02. YMMV

Ventile is a very high density weave long stable cotton fibre material. Not all cotton, nylon, polyester, polycotton or wool etc fabrics are created equal.

Material Attributes.

Comfort and warmth
Breathability
Quiet non rustling
Weight
Wind Resistance
UV Degradation
Water Resistance
Water Proof
Fire Proof
Wide Operating Environmental Temperature
Durability
Ability to Repair
Ability to dry quickly
Cost

I wouldn't say that any one synthetic fabric is superior than a natural fabric material such as Ventile as Ventile Cotton will have lots of excellent attributes, which will be useful in the Wilderness. Same issue with Polyester fleece v Wool.

Ventile had been used for around 70 years now for RAF fighter Aircrew; it still has yet to be replaced with a synthetic.

But if operating in an Environment such as a potentially very wet and windy environment i.e. Scottish Highlands then Goretex/Event/Ceramic Triple Point would probably be preferred material due to its superior attributes of Waterproofness and weight over Ventile.

I'm a big fan of these: Fjällräven G-1000 trousers
A blend of 35% cotton and 65% polyester.

Breathes really well, very comfortable (even when wet) and dries really fast. If it only rains a little I won't bother, but when it pours rain or really wet snow I'll augment with waterproof trousers (gore-tex equivalent).

For the record I also used this heavy-duty Norrönna canvas jacket for many years. 100% cotton in a very thightly woven material. This works really well in sub-zero temperatures. It works OK in sleet. In rain it's not optimal, but it won't kill you either: It takes quite a beating before you get soaking wet, and it will keep the wind out even when wet. But there is a reason I didn't buy another one, but replaced it with goretex. http://www.norrona.com/Products/0118-07/svalbard-arktis-cotton-ano-jacket-mw
The properties of these canvas-like materials have very little in common with your average daily wear cotton material, such as jeans. Jeans are close to absolutely lethal in anything but extremely dry outdoor settings.

EDIT: Recalling fond memories about the trips done with this jacket I also remember the marked shift in water repellent properties that occurs around 8-10 Celsius. Below this temperature it sort of works, it'll keep you adequately semi-dry for quite a while. Wear wool underneath and you're OK. Wear it in the rain above 10C and suddenly I was instantly soaking wet... As I said, there's a reason it is a nostalgic memory replaced with gore-tex equivalent.

Environment has a great deal of influence when it comes to selection of fabric. Cold & wet I stay clear of cotton. On a flight line with jet engines and JP-4/5/8 I stay clear of polyester and nylon prefering cotton, wool & nomex depending on season. For high wear situations it's hard to beat nylon canvas such as the heavier weight nylon pants from 5.11 & RailRiders, but cotton and nomex have their place too.

I learned about Drop Zone Tactical (DropZoneTactical.com, DropZoneTactical.com/clothing/clothing.php) on ETS a few years ago.

I spent a lot of time talking myself into trying them, since they are quite expensive for rugged wear clothing. I am glad I did. Now I wear nothing else until it is time for a truly dress-up occasion.

They are cargo pants, so that may affect your plans. The fabric is 12-ounce per yard 65/35 poly cotton blend. The pockets use the same fabric inside and are deep enough that I rarely use the cargo pockets. Knees and seat are both double layer. Waist is adjustable.

I have them in navy blue and I find that the dark color deemphasizes the external seams of patch pockets and double layers. I have simply added a blazer for events one step more formal than casual Fridays. (The navy blue is quite a bit darker than the example on the web site.)

For cold or cold/wet, I use wool. For a pant you can wear to the office try ex military wool serge or twill uniform pants. I haven't bought any recently, but they used to be available cheap and in near new shape (no one wears a dress uniform very often any more).

For warm or warm wet I still use denim. I am not comfortable with nylon around fire and Nomex is too expensive. I did once have a pair of Cordura coveralls (to cover my dive suit in nasty places) that would have made very rugged pants, but was never able to find any of that weight.

Respectfully,

Jerry