if you pair a z'd frame with a pancaked crossmember you wont have to raise your engine as high and may be able to avoid raising the transmission hump. just an idea. if you havent looked into pancakes check this out.
here
its a bit more work. but, Its going to be hugely worth it. the biggest problem with a z is how high it places the motor afterwards. I dont know why this isnt just the standard with z'd frames, but it should be. also, I/m sure you have already noticed from the other builds that z their frames, but If you angle your z, to move the crossmember forward, it will help center your wheels in the wheel well.
one last thing, I know you don't want a dropmember. but, I think porterbuilt offers a narrowed control arm kit to suck the wheels in so you can actually steer your truck with its slammed. which you wont be able to do with just a normal z