Don't you know 67-72 Suburbans are rare?! They have three doors! You'll ruin the rareness!
j/k.
It's a running joke around here. I'm just clowning around. Don't know the answer other than to say it is possible, as are most body fab changes. I'd expect you'd have to weld in driver's side B & C pillars from the pass side of another burb. 3rd door rocker, also. Maybe the pillars' left/right orientation might add a hassle, too. Now, I'm lost.