For light touring there is no need for wide trekking rims unless you want wide tyres too. A standard 36H rim will do. Here is a design I would recommend as a very strong, but reasonable light weight wheel set:
http://www.rosebikes.co.uk/article/xtre ... aid:339578It has Shimano Tiagra 36H hubs. They are really nice, and despite not being expensive, easily surpasses many hubs in factory wheels. They are cup-and-cone design so they can take a heavy load, spare parts for them are cheap and available everywhere, their sealing is excellent so riding in heavy downpours doesn't wash out all the grease. I bought mine some years ago for my winter wheels to spare my expensive Ultegra hubs, but I have been using them daily on my commuter bike ever since.
DT Swiss Competition spokes. They are swaged (DB) 2.0/1.8 mm, cold forged stainless steel, high quality spokes from are well known manufacturer. Recommended.
The rims are fairly standard 500g rims, with double SS eyelets, and made of 6061 T6 aluminium.
http://www.rosebikes.co.uk/article/xtre ... aid:333724I think they are rebranded Rodi rims.
The design: 36 spokes in a 3 cross configuration is very strong. Probably has a static load bearing capacity of +400kg. All the parts are excellent too with spares available, and the price isn't bad at all. Rosebikes also have an excellent reputation too, but my point is not so much to recommend exactly this wheel set, as to show that a good all-around wheel set with a sound design doesn't have to be expensive.