Planning to turbocharge a 99 Jeep Cherokee 4x4 5 speed.The 4.0 engine will get forged pistons for sure....But what about the stock crank and rods? Are these,when properly prepped, suitable for let's say 10-12 PSI boost for short durations at no more than 5000 rpm?

As an alternative to building the 4.0 and then turbo, which if you have the 190hp 4.0 at 10 psi would be ~ 320 hp

Consider doing an engine swap to the GM 4200 - they are either 275 or 290 HP stock. More than a few have turbo'ed this engine and are getting 425HP @ 8-10 psi on a stock block engine.

At the end of the day its probably equal work to do the 4.0 build and the swap and your 100 hp ahead.

Complete engines with all the parts inc. pcm/harness etc can be had for ~$1600.

extras on top of that are:

Jerry W. flywheel
adapter plate
oil pan ?? not sure where the stock sump is on the 4.0
and custom engine mounts
limeswap PCM fix/harness mod

google vortec4200

I see a 4200 swap as being a major pain in the ass.Take a look under the hood of a Cherokee,the front sump,tall wide 4.2 would require many modifications.
And I don't a Trailblazer engine ,I like the OHV inline 6

The 4200 is a front sump engine so thats not a problem. Suit yourself.

What I mean is the 4.2 has a front sump and the engine needs a rear sump to clear the front differential.
Add to that adapting the Jeep 5 speed to the GM engine. And the mentioned wide top end of the 4.2 makes problems finding room for for AC and power steering.If the tranny/tranfercase needs to be relocated fore or aft to accommodate the 4.2 that means driveshafts and linkages to deal with.
I've swapped a lot of engines,some difficult,but for this vehicle it's my opinion just because the 4.2 can make more power doesn't make it the right engine in my case.

But anyway,for the record,I measure the 4.0 inline at 27 inches overall length,and 17 inches tall from the oil pan rail to top of valve cover . And it's a tight fit in the Cherokee front to back and just clears the hood in the front.