Quite frankly an intank or hang on refuge would have minimal benifit to your tank unless you can get them in a size that wil be 10%+ the volume of the tank. While its always "bigger is better" when it comes to fuges and sumps a good suggested size is 20% of the main tanks volume. I shy away from anything in tank because that just ends up taking away room for your fish to swim.
__________________ Remember dont tap the glass, your fish will think you're an idiot-Anonymous mother
you would need a stronger pump to get the same GPH but sure it could sit on the floor.. my guess is the dresser is taller then a stand but if not it wouldnt really be any diffent then under the stand..