Custom tank idea

A friend of mine has taken out his old fireplace and would like to build a
custom tank in it's place. He has no experience with fish so he's asked me
for help, and I'm turning to all of you for ideas. 

What we have to work with is about a 36" W x 48" deep x 24-30" tall area (a
fairly big, box like tank) sitting just off the floor. It's a concrete slab
so I suggested that we build a 1-3" wooden platform to put the tank on. 

Since the tank is on the wall that seperates the kitchen and living room it
will be visible from both sides. 

Side view:

livingroom           kitchen
           |wall |
          _|     |_______
         |               | 
         |               |
         |               |
         |               |
         |               |

We are toying with the idea of the following for a filter: a large
hydroponic tray above the tank with rock wool and various herbs, and other
plants growing in it. 

Of course, we'll have to work out some sort of system so that if the power
goes out there won't be an overflow of water comming into the tank. 

Some things I'd like to hear from you all is, what do you think of this
filtration method? What type of glass and thickness would you recommend?
Should he attempt to do the work himself? What type of sealant should he
use? How many tubes dow we need for lighting? 

I've also suggested that we go with a rich substrate with heating coils -
since this will be a very heavily planted tank. 

Thanks for the input. 

- Paul

Paul Evad (aka Ded on Shadow's Edge)  "Instead of letting doubt decide
pevad at islandnet_com                      what you will do, decide what 
http://islandnet.com/~pevad/Kudos.html     you're going to do with your