Is there by any chance a central donation system for plugin makers (and WP if that's appropriate).
I was hoping there might be a system that:
could let you make one donation for makers of plugins the donor designates,
fairly allocate the donation on the basis of the quality of the plugin (e.g. sophistication and complexity [time-spent and skill of plugin maker as estimated by experts who could estimate such things], value and usefulness, etc.)
send the payment to the plugin makers.