I have a copy of "A Handloader's Odyssey" by Stan Watson, copyright 1999, wherein he did precisely that - take the .30-06 up to higher pressure levels to see what it would do. Stan used an Oehler System 43 and two .30-06 rifles, a Model 700 and a Model 70. Some folks here will remember him, he used to post as OKShooter.
Just as some examples (I'm not giving the charge weights):
150 grain Sierra at 63,800 psi gave 3133 fps with RL-15, 24" M70.
150 grain Sierra at 58,700 psi gave 3055 fps with H380, 24" M70
165 grain Hornady BTSP at 65,900 psi gave 3015 fps with IMR-4350, 24" barrel M70.
165 grain Hornady BTSP at 66,400 psi gave 2983 fps with IMR-4350 in a 22" M700.
180 grain Rem. PSPCL at 66,000 psi gave 2954 fps with H-4350, 24" M70
Same bullet at 61,900 psi gave 2872 fps, H-4350, same rifle.
Same bullet in a 22" M700 using RL-19 gave 2707 fps at 60,400 psi.
Hope that helps.
Now, just for the usual caution - I wouldn't go anywhere near those velocities unless I had an Oehler 43 myself. 3133 fps with a 150 grain bullet and 2954 with a 180 is flat out
cookin'!. Stan was a ballistics consultant for the military for many years and knew what he was doing. I'd bet there's not one in a thousand handloaders who could really tell you with any precision (even within 5,000 fps) what their loads are
really doing in their particular rifle with their component lots.
But this does give one some comfort to know that if you stay at 2950 fps with a 150 or 2850 with a 165 grainer, using suitable powders of course, you are very likely in safe territory. And everybody repeat after me, "and the animal will never know the difference!"