Another option is the .30-06 Ackley Improved. I know a fellow shooting one of these and he just loves it. You can still shoot factory .30-06 ammo for fireform brass (or in a pinch if needed). This fellow used to have a .300 Win Mag Encore Barrel, but for some reason decided to sell it in favor of building a .30-06 AI (had a factory .308 barrel rechambered). He tells me the .30-06 AI will achieve almost the same performance level as the .300 Win Mag, but with less recoil.
So yes the .309 JDJ is a possibility as it is basically a shortened, rimmed .30-06 AI.
SD Handgunner