I am upgrading my wheels and this is a bit of a process:

The Rims I purchased from Ray at Derby Rims . They are 26" by 40mm external width (compared to 29 for my current Sun Mammoth) and internal width of 34mm. I purchased the Downhill version which are slightly heavier (465gm each)and stronger. They cost

The rear hub I extracted from Brett (my brother in law) as he had won it many years ago and it was brand new... cost $800.
I then needed to upgrade the hub to disc compatible and add an external gear mechanism. This is being done by Paul and Rohloff Australia costing about $400.

I am getting the wheels built by Greg Ryan at TWE and the from hub them also.

Going for internal nipples with washers to reduce the stress on the rim.

Tyres:
current thoughts:
FRONT: Schwalbe Hans Hampf on the front and although the "trailstar" compound is supposedly softer and therefore preferred on the front there is a possible weight penalty (1015gm Trailstar to 665gm Pacestar although the Schwalbe site is confusing and lists 2 weights for Trailstar, one the same as the PAcestar??) makes me prefer the Pacestar. I'm going for the 2.35 width. Available from Chain Reaction at $68.99 or Wiggle for $65.88
REAR: Schwalbe Rock Razor on the rear and definitely the Pacestar which is recommended for the rear. It is a fast low rolling resistance tyre at 665gm and at Chain Reaction for $72.99

Rim Tape:
Ray at Derby recommends Stans 19mm rim tape but Chain Reaction only has a 21mm here at $19.49 for 9m (enough for 5 rims)

Also need Stans solution from Chain Reaction at $20.49 for 473ml.

Finally need 44mm Presta valves which I can only find at Chain Reaction for $21.49