Toadslop, Look up the Fuji Touring. It's a little more heavy duty than you may need, but there is few equals when it comes to value...the rear rack is included which is a further saving. Now-a-days I advise all OEM and off the shelf wheel sets be stress relieved, re-tensioned, and re-trued as so many are machine built. This is an extra expense (I have no idea how much extra.) and well worth it.
26" wheels are slightly stronger than 700C wheels if all other things are equal, but 700C has proven to be quite reliable for even heavy loads if built correctly.
Brad
PS Unless you have a good stash of spare parts, buying a complete bike is cheaper than building one.