I have managed to convert the bottom bracket to work with three piece cranks on my early 1970s UO-8. It originally had cottered cranks. All I had to do was find a square taper bottom bracket spindle that had roughly the same spacing with regard to the bearings as the original. I reused the bottom bracket cups and used loose bearings. I had problems with unthreading on the driveside bottom bracket cup (it's not reverse threaded) so I used thread locker.
It works okay. The quality of the only spindle I found at a reasonable price was not great, so it's not the smoothest (there may also be a slight mismatch in the bearing surfaces).
Any of the more specific modern cranksets will probably require one of the more expensive bottom brackets with interchangable cups, such as the Phil Wood. However, if you're considering an outboard bottom bracket you will need to think about whether you need to face the bottom bracket shell. I am only familiar with using the Park Tool bottom bracket tapping and facing set for this purpose, which normally is used to face the bottom bracket shell after tapping. Looking at available tools, it should be possible to face the bottom bracket shell with a headtube facing tool if you find it necessary to do so.