If you are looking for the most ergonomic riding position, you should give some kind of recumbent bicycle a serious consideration.
I don't have any references to data, and soreness is subjective. But in my personal experience, the recumbent and velomobile riders on longer rides (Paris-Brest-Paris 1200 km, London-Edinburgh-London 1400 km and such) are the riders reporting the least amount of posture-related problems.
You can still get sore on a recumbent if you overload your knees and leg muscles. But a reasonably fitted recumbent bicycle is probably the most ergonomic ride you can get: Your weight is spread out over a proper seat, your hands and arms are neutrally positioned and don't carry any load, and your back is supported. Also, almost every recumbent seat has a slight turn at the top to support your neck, and many have an ergonomic headrest (preventing problems like Shermer's neck).
I ride recumbents myself for longer brevets and touring, as well as "regular" bikes. The different in comfort on longer distances is noticeable, and the most interesting part personally is that you can increase your distance remarkably fast without soreness penalties. I have finished both 300 km sportives and longer brevets (up to 2100 km), and while the legs muscles feel quite worn, and I may look forward to some sleep and rest, my back, wrists, and seat does not hurt.
If you give recumbents a try, you should check the angle between your shoulders, hips and the bottom bracket. A large angle, with the three above almost in a straight line, is similar to an upright "city bike" - and may limit your power output, as well as put a bit too much weight on your seat. This could be the case for some older recumbents like the Tour Easy.
A sharper angle between shoulders, hips and bottom bracket is more similar to a typical road bike position, just rotated backwards and supported by a seat. This is typically found on short-wheelbase higher bottom bracket recumbents, like the Bacchetta highracers or the HPVelotechnik Speedmachine.
(a Schlitter Encore high bottom bracket road recumbent pictured below)