Red, if I was to build this size tank in beween 2 rooms as a wall unit to be seen from both sides, I would have it heavily reinforced.
As for cleaning, you can install hinged doors above the tank to access your lighting and for cleaning.
As for lights, I would go with some high wattage MH, and be sure to insulate above the lighting to prevent fire, and some good ventilation by exhaust fan(s). It will have to be some heavy duty glass, also. It has been my experience that the thicker the glass, the more expensive. By this I mean - just for my small tank that I am building, the 3/8" glass was well over twice as expensive as 1/4". You may consider tempered glass, safety glass, or acrylic.
Although acrylic is stronger than glass compared to it's thickness, I just feel that acrylic is too easily scratched. I just personally feel better about glass.