The Ural with the driven side car.
Ideal round the world motorbike. Particularly if your wife wants some luxury's to be packed, and not be constantly squished in some where.

After all at this point Your riding RTW on a form of open vehicle, and you are not in a rush.

The Urals are amazing off road. Saw one riding up a very heavily rutted forest path I was walkig up and it struck me with how easy it trundled over things.
I know filtering is frowned upon with an outfit but two up this isnt going to be as much of a hinderance as a magical bike on bad roads with a simply bottomless cavern for packing space.

The new ones are reputed to be reliable (or some derivative thereof) but mostly they are fixable. No other bike comes with a DIY service manual and a warranty to cover it if you do your own servicing!

You will have great fun on the bike and having two seated positions for your wife, (either pillion of in the side car) means that she has some scope for movement from the monotonous positions. Also Off road she will have great fun keeping you upright, and watching those guys go up that track, it really is a teamwork thing.

If I were going on any looong trip and planned to go two up, I would buy their "Ranger" (also called "Gear Up") and I would change the paint scheme from Cammo plus reinforce all the pannier mounts.

Ural Motorcycles Europe | Ranger

Its certainly a bike that has really got my interest, one of these days I will get one, but I do want the powered side car drive with reverse. Just have to be careful in Right hand drive countries if I get the opportunity to overtake
Heh heh heh!

Other than the Ural I'd say the BMW R1150GS, I have the RT and its an amazing bike (more technically minded folk will say get the simpler R100GS) The 1150 basically doesnt notice it when my wife is on board with me, fully loaded and touring, plus it returns my most economical runs when we're two up. 315 miles from one fillup of (about) 24 litres. Wow!

I've been astounded by the R1200GS its handling and road manners are impecable (other than the mirrors swatting every White van you see)
But as a bike its kind of like going to the Mayors fancy ball wearing a ski mask, that phantom of the opera chap pulled it off but it just doesnt go down well. Likewise this bike is sort of a road bike but it looks like it should be in a bog spraying everyone with mud. I wouldnt take the newer 1200, cos... I just wouldnt!
Having said that I genuinely loathe those theiving ***** BMW dealers, I have yet to come back from one without the feeling of being royally shafted. Hopefully beelzeebub has a special plan for them.

P.S. If you ever get the opportunity to take a ural for an off road spin, do it, it will make you laugh. Thats what it is all about

Cheers G