I feel that a wet sump system can work to some pretty high horsepower levels without problems. Noelke runs one on his monster truck, I don't like it but to be fair it's been ok.
The real secret to a wet sump system is to have a nice big oil pan that's baffled for good oil control. Not getting it over full on oil and having a proper pickup are all important factors.
I believe that the pump starts to get in the way when you go to more than a 4.750 stroke, no problem below that even with an aluminum rod, some pickups might need a little work however but no big deal.