After much searching the best I have come up with so far is this:

http://www.hedcycling.com/ardennes/ardennes-plus/ardennes-plus-sl

Rims are 25mm external width and 20mm internal width @ 465g. Rims are available on their own (known as the "Belgium +")

Lots of positive reviews abound:

http://www.bikeradar.com/road/gear/category/components/wheel-sets/product/review-hed-ardennes-plus-sl-47670/

http://www.slowtwitch.com/Products/Things_that_Roll/Training_Wheels/Ardennes_long_term_review_4056.html

Granted it possibly shows that my earlier choice was excessive (as pointed out by JohnnyNT) so now I am looking for a carbon equivalent.

Was feeling pretty pleased with myself last night after picking up a set of very reasonably priced DT Swiss hubs. Now feeling not so pleased as I am trying to figure out what would be a good compromise rim (preferably some sort of chinese carbon )

This wheel set will be running on my CX bike which I hope to race next season (for the first time) and I will also be doing a couple of CX sportives (off road endurance rides). For the sportives I plan on running WTB's 700 x 40C nano tyre tubeless and fairly low pressure, I thought this rim from light bicycle would be a good choice:

http://www.light-bicycle.com/wider-carbon-mountain-29er-rims-clincher-tubeless-compatible.html#.VOtNQ_msWLA

These rims have a nice thick rim bead @ 3mm and are relatively light whilst being quite wide (ID of 24mm) but I am nervous of the 40psi max pressure. I like the idea of the (relatively) large volume for the 40C tyre and the wide rim + low pressures, seems like it will make the bike a lot more pleasant to ride, not to mention faster off road.

For racing I am guessing I will have to go to something narrower (isn't the limit around 33C?) which presumably will need to be a higher pressure? Whilst I am sure I wont be heading for road pressures 40psi doesn't seem like it leaves much room for maneuver, I would like to stay tubeless for the races if possible.

Does anyone have any bright ideas? Is an ID of 24mm to much for CX? All of the CX rims i've looked at seem to be a lot narrower.

Many thanks,

Mike

Can see that there isn't much room! but what's the best thing to do? Can always go with a thinner NN in January I guess. Doubt helicopter tape will do much good?

Brilliant! Thanks for the info.

Need to run the brake lines internally (256SL frame) so is it better to split the lines at the brake lever or the caliper? Presumably if you split the line you might just as well drain the line completely? Also do I need some sort of adaptor to run a 160mm disc on the rear of the 256SL frame?

Many thanks,

Mike

Finally got the bits in my hands Pictures and weights to follow.

Thankfully only charged VAT, with the Parcelforce "clearance" charge it came in at £37. Bits should arrive Friday.