So I already posted something similar in the fan fiction section under the name USS Ulysses, until I discovered that the name Ulysses is actually taken by a Nebula-class starship featured in the DS9 episode "The Adversary". The idea was inspired by my little Playmates Excelsior-class starship mini playset, and the fact that it was so bulky and disproportionate in comparison to other Excelsior-class models. So I researched all existing Excelsior-class ship names, and came up with the USS Atlantis. Here's the basic idea behind the design:
In the late 2360's, Galaxy-class starships were proving more and more successful in bringing peace to the Federation. One appealing aspect of the Galaxy-class assignments were the inclusion of extra space and facilities on board for families and civilians. As more and more families went into space, the need for other starships to be upgraded to meet the needs of civilian space travel became more apparent. Thus, Starfleet ordered a number of older ship classes to be upgraded to be more "family friendly." This was the idea behind the USS Atlantis.
The Atlantis began life as an Excelsior-class refit of the same sub-class as the Enterprise-B and the Lakota. After the vessel was chosen to be the testbed for the new upgrade, she was literally rebuilt from the ground up, using existing materials to create what Starfleet termed "Experimental Configuration #3".
Below are images and statistics regarding the "Experimental Configuration #3":