i really have no clue on any sites that have complete plans, most of the design will be up to you. here is one that i liked on AA:
page 3 has some hood pics...
as far as the hood that i built:
i used 1x2 poplar for the interior frame of my hood. i built the frame to the exact dimension of the outside of the tank bracing. i skinned it with 1/4 inch oak plywood. i used the oak plywood to cover the black plastic bracing. i used crown molding at the top and 1x3 oak at the bottom for trim. the doors are not made yet, nor is the top. but for the top, i am going to make a simple hinged surface the opens towards the back. i will probably use a folding table leg brace to hold the cover in the open position.
things i would have done differently... instead of doors, i would have made a front panel that opens up the entire front. also, i would have built a different support for my lights, but since i use a coralife 4x65, the details will not really help you.
kinda a brief description, but you might be able to understand it. i may post a pic or two if i remember tonight...
most important is to plan ahead, know the size of all the components that you want to put in the hood. and also, know how big stuff will be that has to pass through the hood to get into the water... i have no way to take out some of my rock without taking my lights out of the hood and removing the rock out the top of the hood (not that it happens often, but it is a pain when it does)