It's possible and either easy or incredibly easy, as there are 2 ways of doing it.
The easy way is to edit each research file (lRESEARCHSUBJECT_MAXSHIPSLOTS 0>7 for each race) and increase the number of fleet points it adds. You can do the same with the MAXCAPITALSHIPS research to increase cap ship crews. Easy, but will take a few minutes since there are a bunch of research files.
The incredibly easy way is to open gameplay.constants and change the fleet supply scalars:
Right now, playing with Large fleets gives you a 1.25 multiplier (25% increase in FP gained each time you do the research ). You can just change it to 2.0 and your standard 2000 fleet points will be doubled automatically for each research when playing with the Large setting.