I can't recommend a specific retailer but can offer two tips. Although GBs generally have excellent hafts, sheaths, edges, etc., I would ask a retailer if: (1) They will hand-pick one with really straight grain in the wood and (2) they will take the sheath off and check the edge and sheath before shipping it. Tell them you're kind of picky about the grain of the wood.
On rare occasion the axes can get bounced around in shipping. This can cause the edge to bang against the rivets in the sheath. I once got a GB with a couple minor scuffs on the edge and a couple severed rivets in the sheath (over a dozen other GB axes I've bought had no such problems). The tiny edge nicks came out with a fine diamond steel and the seller immediately sent me a fresh sheath, so now I have two if I want to replace a couple rivets on the first one.
When you get the axe, be cautious when you re-attach the sheath after using it. The sheaths can sometimes be a snug fit and if you just slap them on, you may slice the leather with that razor sharp edge. Also, read the axe booklet that comes with the axe.
Gransfors told me that the factory puts a convex edge on their axes when they do the final finishing. If you want to maintain that edge the way it came from the factory, you'll want to bear that in mind when sharpening.
You'll really enjoy the axe when you get it!
DancesWithKnives