Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - What's a good LD Wheel?

I'm currently running a set of neuvation R 28 SL2 wheels. Would these be ok for long distance riding? I guess I'm just a little nervous about the relatively low spoke count.

Here's the info from the neuvation website:

R 28 SL2
# 1530 Grams per set *
# Shimano 8, 9 and 10 speed or Campy compatible
# Deep V 27 mm CNC silver sleeved 420 gram rims
# 20 spoke front, 24 spoke rear
# Silver Stainless steel 2.3, 1.7, 2.0 triple-butted spokes
# Alloy nipples, brass drive side rear
# Forged alloy silver anodized hub shell with cut outs
# Forged alloy cassette body easily changed between Shimano and Campy
# Precision-sealed cartridge bearings with dual seals super smooth
# 7000 series alloy axles
# With normal travel quick release levers
# 700C Clincher

http://www.neuvationcycling.com/wheels/r28sl2.html

If I did get a more heavy-duty wheel, should I get both front and rear or would I be ok with just swapping the rear? I plan on using a rack & trunk with no handlebar bar or any other weight up front.

What's a good LD Wheel?The wheel you finsh the ride with --without thinking about it.

I see no reason for any special wheels for brevet riding. Presumably, you bought a quality wheel that is good for many miles. Brevets generally do not require heavily loaded bikes and so do not require extra-stout wheels. If you are planning to do loaded touring, it would be another story.

If you do decide to get new wheels think about building up a front wheel with a dyno hub for battery free lighting.