I came across these tanks at a show and picked up three homemade tanks of this configuration.  It is a front opening setup that is very simple and easy to use.  The door rests between the two glass sides and up on two glass "gutters" at the top and bottom.  To open the tank, you simply pull the top of the door away from the tank.  The door can be completely removed for maintenance or photographing.  Also, note that the bottom right front part of the bottom is drilled so it can be fitted with a bulkhead.

The following diagram is of one of the tanks with a few modifications.  One could adjust the dimensions to suit their individual needs.  This configuration results in approximately 20 gallons of capacity and 2.2 sq. feet of floor (a normal 20 gallon tank has 2 Cubic Feet)  The glass is 1/4".

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                        Top part of Door                                                             Bottom part of Door

I just setup one of these and hope to set up the other 2 the 1st part of 2000.  Once I get them set up, I will post more photos.