Well, I was initially going to suggest the KH29 with the Knard, but you say you weren’t so thrilled with the 29 wheel size. However, if I remember right, the diameter of the Oregon 26 will be pretty close a “normal” 29… so why do you expect to feel comfortable on an Oregon 26 with almost the same diameter just because it has a fat wheel (which then weighs more than 29)…
I personally have not tried a truly fat tire (just the Duro on 24 and 26), so take that in account when reading the following:
Beyond that it’s hard to say without having up close and personal experience with the trails you ride. However, if you’re riding a 36 muni on trails, then shouldn’t you feel totally at ease on the 29? In my case after doing 36 muni I found the KH29 felt way smaller than I was expecting. Or do you intend to ride totally different trails?
After riding a KH29 and then a Nimbus 26 Duro on my 3-month summer trip, I expect to pretty much abandon the 24 (the 29 was borrowed and I brought the 26 home with me) and use 36 for XC stuff and the 26 for steep alpine stuff.
Hmm… other than that: for me the 26 feels no harder to ride for any steep stuff except “trialsy” stuff where you hop a lot (and then weight is almost as significant as raw wheel size). But the 26 feels way faster and more fun (i.e. speed in corners and such). I think the 26 feels closer to the 24 then the 29 to the 26 (I’m not doing the math now, but I think the effective diameter differs by close to the same ratio) but the 29 to the 36 is a whole different animal. Unfortunately I didn’t ride the 29 and 26 on the same trails, so I can’t really do a fair assessment. However, I feel like I could have handled the 29 for all the more difficult trails I did in Oregon/Washington/BC on the 26 almost as well except for the drops and skinnies, where any bit closer to the ground feels safer.
So I’d think the choice would be between the KH with the Knard in either 26 or 29 (I am pretty sure the Knard comes in both diameters, right? or only the 29?). I think you probably be pretty happy with either… so it’s just the question of which one is more ideal.
I am only speculating, but I envision the fat tire to only have real advantages if you ride unusual surfaces like snow or sand. Otherwise, it’s gonna be heavy, so if you feel the Duro is dragging you down, then the fat tire shouldn’t be any different? (someone with actual fat tire experience feel free to correct me). At the Seattle Muni Weekend almost all the top riders were on Duro-like 26 munis with a few on super lightweight 29s (the Knard I think). Though the style of the trails also required some hopping so not being too heavy was I think important.
Hmm… I’m just going from memory here, but isn’t the new KH 29 the same width as the KH 26? Then maybe buy the 29 and then if you don’t like the wheel you can switch out for a 26 with not much trouble/expense… i.e. maximum long-term versatility? I’m way taller than you (6’1") so maybe it doesn’t work out so trivially as for me?? but the 29 frame is only a tick taller then the 26. I think the KH29 with the Knard can be built up to be much lighter than your average 26… (e.g. Tom from California has a KH29 that is insanely light and for the SMW he rode almost everything the others did on 26 except he was better on uphill climbing — yes, better on the 29 than the 26. OK, much of it is will/desire/effort as many didn’t care to try)
Or if you’re really looking to replace with 24, then the 26 may be a great choice. On the other hand, if you expect to still ride the 24, then the choice of muni 24, 29 and 36 would seem to make more sense than muni 24, 26 and 36, as then you’d have so little difference between the 24 and 26 (one will probably be neglected).