Headset and stem? - no opinion on whats best. I use a Thomson X4.
Handlebars - Very happy with my Jeff Jones H Loop bars as I ride upright and they offer multiple hand positions including a lean forward emulating a drop bar amount of lean.
H-BAR
Saddle is a very subjective choice and what works for one does nothing for another. I'm happy with either my B17 or for rougher roads my Flyer Special.
Seatpost - I picked up a setback Thomson Masterpiece for around the same price many stores sell the Elite. Either would have been fine for me.
Cranks - I'm a fan of low gearing. The lowest you can go within warranty (my preference) is 34T when utilising a 16T sprocket on the hub.
A 110 BCD (bolt circle diameter) is the largest BCD crankset to allow 34T chainring (If I'm not mistaken). I use a Thorn crankset but to
me, the important bit is the Thorn reversible chainring, which when worn can be flipped, as can your Rohloff hub sprocket. You don't
need a Thorn crankset, but I believe a reversible chainring is a decent choice.
Thorn 110mm 5arm reversible SINGLE ring - Black - £34.99
Brakes, I'm a fan of disks so it was BB7's and Speeddial 7's from Avid for me. I'm a cable fan for ease of maintenance in the field.
If your preference is V-brake, I've heard good things about those aforementioned CSS coated Andra rims, as used by Thorn Cycles, but
believe they are recommended paired with a certain coloured Swissstop pad which is a little pricy.
Fenders - again a subjective choice, but I happily rock polished stainless steel Gilles Berthoud and am happy with them.
Racks - I believe Tubus are the benchmark. I use stainless Cosmo and Nova due to not liking scratched paint or rust, however their plain painted
cro-mo are likely a bit stronger and maybe more easily repaired in the field assuming not everyone can wield stainless.
Dynamo hub - I'm very happy with my Son28 matched with E-werk and cache battery. This manages to keep my Edge 800, iPhone and Petzl
headlight torch (for reading or putting up the tent after dark) charged on tour as well as providing power for my lights. I use an
Edelux headlight and Phillips Saferide lumiring taillamp.
Waterbottle cages: - big fan of BBB XL Fueltanks and Nalgeen 1.5 litre bottles.
With regards disk brakes, I have them on both my Son28 front wheel and Rohloff rear. I recommend the threaded axel if using horizontal dropouts like on Surly's
Hope this post helps in your search for consensus with regards researching for purchase decision.
Good luck