Finding hoods for tanks is becoming more difficult, probably because there are now so many lighting options. I know I went through this with my 40g I bought three years ago.
The easiest option is a glass cover unit which you can get for any of the basic aquarium dimensions. These sit down inside the frame on the lip that runs around the tank opening. Then find the lighting unit you want which sits across the tank frame above the glass cover.
The glass cover sets will have some sort of hinge so the front third will open up; this is what I have on my 40g and 10g tanks. Or with a 4-foot tank you are more likely to find the glass cover sets that are four rectangular panes of glass with plastic runners to sit inside the frame on the ends and one across the middle; I have this on my 4-foot 70g and 90g tanks.