I have a Kona Jake the Snake for my commuter and for weekend rides with my mates, but so far already had a cracked frame which was replaced under warranty but two years later, the replacement frame has cracked again in the same place. I'm putting it down to the fact it's an alu frame which probably isn't that well suited to commuting, what with fatigue and all that, and also I'm a big guy - not seriously overweight - 6' 6" and heavy-built.

So I've decided it's time to go for a steel-framed bike, more durable and should last much longer. I'm after something similar to the Jake the Snake, that can take mudguards and a rear rack, and handles the commute and weekend road-blasts with ease. In the past I've always thought about the Surly LHT or CrossCheck, but I'm not so keen on the groupsets and wanted something with a carbon fork, just like the Jake the Snake, so I've come across the Norco Search S1 which seems fairly close in spec to the Jake the Snake and is a steel frame so it might be an ideal replacement.

I've also come across the Charge Plug 4 and the Charge Plug 5 (though the Plug-4 has the 105 groupset which I'm happy with) but they don't have carbon forks, but I guess you can't have everything.

Any other suggestions for a steel-framed adventure / cyclocross bike that can take rack and mudguards?

Thanks in advance.

What is your budget and preferred maximum tyre size?

It is worth considering genesis Croix de Fer, which has 105 and a carbon fork.
Croix de Fer 30 | Genesis Bikes

Also the Salsa Vaya:
Vaya 2 | Bikes | Salsa Cycles

Thanks, I should have stated max tyre size and budget, the latter around £1500, the former 38mm maximum width for tyres.
The Croix de Fer 30 looks great but it's out of my budget unless I can pick up a discounted 2014 model or go for the 20 which doesn't have the carbon fork or 105 groupset. The 30 looks great though with nice Reynolds 725 frame and hydraulic disc brakes it's tempting to blow the budget or maybe play the waiting game for a discount.
I not sure where I'd be able to buy a Salsa Vaya and I certainly don't want to mail-order my bike.
I've discounted the Charge Plug bikes as at 58mm max size they'll be too small for me, and for the money £1200, the Norco Search S1 has the carbon fork and the groupset.

I'm surprised that as a larger rider who has already cracked not one, but two aluminum frames, that you would consider a carbon fork. You know what happens when those things snap, right?

I've been riding my Charge Plug since January. It's a special combo sold by Performance Bicycles. It's basically the Plug 4 with lesser components. I love the comfort of steel, although it's not as bendy as my 1984 Nishiki road bike...but that's too rubbery. The Plug's front fork is at a nice relaxed angle, but doesn't have the curve of an older traditional bike. I saw that on the All-City Space Horse, which is very similar, but with rim brakes and couldn't match the Plug's sale price.. Anyway, I have a rack and fenders. The SKS Longboards were a little fussy, and they cause some toe overlap when turning. The only other issue I had was with the rear bolts for the fenders and the rack. They are a standard metric size, but not the standard size for mounting racks and fenders. The front fork accepted the bolts that came with the fenders. I believe my Plug's frame is a constant thickness rather than internal taper, which makes it robust...but it is still comfy. I think I would have been happy with a number of similar bikes, but my Plug was $600.

The second cracked frame is a result of an impact with a car, the crack wasn't noticeable but after about 5 days since first back on the bike after the accident, the frame was squeaking and I then noticed the crack. There's a lot less weight on the bike's forks than on the seat-tube and rear triangle, so I'm not too concerned about stresses on the carbon fork.

The Kona Rove comes in steel. KONA BIKES | 2015 BIKES | FREERANGE | ROVE

The Kona Rove looks like a very nice bike, I'll have to check it out at my LBS

Most people are not aware of what happens, because it happens so seldom.
Seriously, ride whatever you like, but there is no reason to try to instill fear into others.

That's strange. No bike frame that fits you should break under normal use regardless of material or rider style. XL size frames are usually overbuilt on purpose.

KHS makes a road bike designed for big guys, a mass manufacture version of a design by big guy bike techie Lennard Zinn. It also has extra long cranks and overbuilt wheels
FLITE 747 - KHS Bicycles
It's not a cross-adventure bike though.

Zinn would also sell you a custom frame of any style but that's spendy.

You could look at older stuff. Really big classic frames are not too common because the demand was small when they were made, but they also don't usually cost much because the demand is still small.

My first Kona Jake the Snake cracked after about 6000 miles of commuting but Kona replaced the frame, citing a manufacturing fault. That frame was hit by a car 2 years later, was checked by my LBS and found to have no cracks or other frame damage that could be seen by the naked eye. About 3 months after the accident, I resumed commuting on the bike and after a few days, I noticed a deep squeaking sound every rotation of the crank; thought it was the bottom bracket so I took a look and noticed the very small cracks on both sides of the seat tube. My commute involves a steep hill climb near home so I guess the frame must've been weakened by the impact of the car and me landing on the frame with all my weight.
64cm and 66cm - jeez that KHS bike is huge! I've never seen such a tall head-tube.

I just realized I linked you to last year's bike. This is current. Not much different but shifting goes to 5800, and two crank lengths.
FLITE 747 - KHS Bicycles