My Toyo 45AII maxes out at 324mm of bellows extension and I wanted to focus relatively close with a 300mm lens. My 305 G-Claron would not allow that so I did a some research and found the modern 300mm lens which has the shortest flangeback of that focal length (without getting into the big and heavy f5.6 lenses). I then bought a 300mm f8.5 Fujinon C which focuses on infinity at 282mm. That gives me lots of room to play and allows me to focus very close to things without getting into add on items like an extension back or a top-hat lens board.

I was quite surprised by the difference in focus distance of lenses of the same focal length, even modern lenses. It's definitely something to consider before buying a lens if you're short on bellows.