I don't know what kind of highways you guys are losing these engines on. Up here in the Adirondacks from i-87 to i-90 which is known for having rolling hills especially into the Berkshires of Massachusetts having a long hill climb to the highest point on i-90 east of the Dakotas I constantly run my cruise control at 70-80mph in 6th. The car never builds boost while under cruise control even through that mountain climb in the Berkshires.
How does cruise control cause such ludicrous cylinder pressures that you're getting bent rods? You'd think you'd be getting this from more severe lugging, there isn't anything wrong with mild pedal pressure in 6th even when starting low at 2000rpm ~60mph
I have an EGR/TGV delete with a Grimmspeed EBCS, 93 octane and flex fuel, dyno tuned at Bren Tuning. 32k miles and I run Motul 5w30 EFE, OEM oil filter