[rpmerf]

At that point you might be looking more at ploping a 69-72 body on a 92-2000 blazer frame / drivetrain / suspension. Don't know if you might be able to use a new Tahoe frame. Might have to cut it down a bit.

This reminds me of an episode of Hot Rod Garage. They took a F100, like early 60's, and dropped it on a Crown Vic frame.

If you go full on restomod, there are a lot of decision to make as to how modern you want to go.
Vortec SBC or LS?
Auto or stick? How many speeds do you want?
4 wheel disc brakes shouldn't be too difficult.

Suspension REALLY depends on how you want to use it. A 2wd with some sport upgrade stuff should be sufficient. If you wanted to swap in an IRS 4wd front suspension, that could get difficult. Don't know how much the rear has changed over the years, but I consider 15 years old to be modern. I think you would be able to find more in the aftermarket that would suit your needs and bolt right in.

Climate control shouldn't be too bad. If dual zone is left / right, grab it out of a car. Car stuff is smaller and should fit under the dash better. Expect to do a lot of cutting and reshaping, or just installing take offs, and running hoses. If you mean front / rear, just grab the rear setup out of a suburban and fab it in. Might need custom lines, but that shouldn't be too bad. It's all made to fit around the wheel wells.

Gauges depends if you want them to look factory or like autometer gauges. Factory will be a bit harder. Might have to reshape the dash to make them look right.