Its for this particular reason why the Amiga failed (3rd paragraph). A browser for 3.x based systems? Oh god, please, MOVE ON. Ditch those old, under specced systems.
Support whats there. Sputnik? Maybe give him some more $ to port that to OS4 (if it isnt already), setup a bounty for THAT project. Help a browser that exists NOW to advance the real operating systems that are in place, not some ol-timey rinky-dink system.
Remember Amiga games? What, do you think everyone ran A500's w/512k ram? Try A500 w/1,2,3 megs, A2000's with 8megs, some with graphics cards.
Good luck, this project will never be completed on a 3.x system.