Tub Drain Retrofit

I am replacing an old cast iron with a 5 foot soaking bubble tub. I want to include a shelf on 3 sides (rear, wide side, front). Shifting the tub 6 inches forward to allow for the rear shelf makes lining up the drain difficult. The drain opening sits just about over the existing drain stub. Obviously a standard tub drain kit won't work. I thought about some combination of drain kit parts, flexible couplings, and PVC joints and pipe. In word, a very messy configuration. Does anybody have any ideas; or should I just forget about the rear deck and go with a standard drain?

The correct answer is more the drain to fit! Do not use any flexible drain components (well, maybe from the overflow as some of those are not vertical).

It's rare when installing a new tub that you don't have to move something.

One option is the Watco "green flexible" drain which does have the outlet connection under the drain opening.

WatcoFlex®