Will paralleling bridge rectifiers up spread power dissipation out to the paralleled modules? AFAIK it should but I want to make sure. Working on a project were heat would become an issue.
Paralleling bridge rectifiers is similar to paralleling individual diodes: you must ensure that currents share equally under all temperature and load conditions.
Unfortunately diodes have a negative temperature coefficient, so the hotter diodes will carry more current, leading to a situation where one of the two diodes in parallel will tend to hog the current.
If you do put them in parallel, they must be the same type diode and close together on the same heatsink to minimize this current hogging effect.