yeah crab0000, i thought of doing that too, but the thing is that i really dont want to see anything in the tank, at all! the way i have the return plumbing planned on the inside of the tank is as follows.
from the 3/4" bulkheads coming from the bottom of the tank there will be a small stubb up of 3/4" rigid pipe, just enough to attach a 3-way 90* elbow. that 3-way 90* elbow will essentially split the dual return into 4 returns. one end of the 90*will be attached the the stubb up, one will point towards the front of the tank, and the other end will point towards the opposite side of the tank along the back. (crappy explanation i know) and on the end of each 90* outlet will be a 45* to controll direction of flow. its like a small series of swing joints, noneof witch will be glued.
after thats in place then il just throw a rock in front of it so it wont be seen. there wil be one on each back corner of the tank.
ill try to draw a picture and post that, but for now, here is a pic of an idea i had.
the idea is for a bubble trap system consisting of pipe instead of baffles. the pipe wil come from the drain and go all the way to the bottom of the sump, then 90* into a tee. one end of the tee will point straight up and have a piece of pipe that serves as a vent, and goes above the waters surface. there could be a series of these tee's with vents. then after the last tee, it would 90* back up and hit another tee. the end of the tee pointing up wil have another vent pipe, and one end will have the water drain.
the arrows show the path of the water, and the little circles represent bubbles exiting through the vent pipes