It is an adaptation of one of the ships made for the Wolf 359 Graveyard Scene as depicted in the Star Trek: The Next Generation 2parter 'The Best Of Both Worlds'.
Nexus, NCC-100452* of the Cheyenne Class is the first in a line of smaller ships i have planned that all use the same standardized saucer section.
Though to be fair, 'seen' is a tiny bit of a stretch as the only time a ship of the Cheyenne Class (the USS Ahwahnee NCC-73260) was shown on screen it appeared as a small spot in the background to hide the fact that no one had damaged the Cheyenne studio model for the Wolf 359 Graveyard Scene (in case you're curious about the canon design of the Cheyenne Class visit ).
