If close is something you want, RB&RZ both have bellows. That plus extension tubes gets bulky but versatile. Rb's with 120 back & either 127 or 90 are around ~$300. currently. The 50 is excellent but you would want a "C" version with floating elements.
Close stuff pretty much rules out the rangefinder cameras of any brand.
Mamiya RB?RZ are the bulkiest, the GS1 probably the smallest.
The Pentax in my opinion is a non contender. It's pretty awkward(for me) to handle.
When comparing weight in order to consider apples to apples Each camera needs to be set up for use. Someone mentioned earlier a light weight body. What does the back and lens add?