The Sparrow class isn't the only design I've been working on. The image below however is one that I think I started over a year ago.
The next on is much more recent, and IMHO takes it further, and refines her. At this point, I have started to think of calling her the Gypsy.
The Gypsy's origins started when I was looking at one of Atolm's designs, which I have been unable to find during a recent attempt to find it, though I remember the story behind her: though I can't remember the name she carried, I do remember it was one of the names of one of the Constitution class vessels lost during the TOS era. She was overall the same as a standard Constitution class vessel, with the exception that the engineering hull was completely redesigned to have the nacelles integrated, akin to the much later Defiant class, but still quite different in appearance. During her trial run, she was accompanied by the Enterprise, which she warped ahead of at significant speed. I remember the term "like a bat out of hell" in particular being used to describe her as she took off at high warp. By the time the Enterprise caught up with her, this vessel has torn itself apart; apparently, the Federation wasn't advanced enough to take full advantage of this type of design configuration, and attempting to do so had lethal consequences.
After a dream the following night where I glimpsed the rear of an engine design, I knew I had to sketch it out, and try to make a whole design out of it. You can see what I remember seeing towards the middle of the first series of sketches. This idea soon turned into a possible replacement for the Intrepid class.
As you can see in the more detailed set of sketches, she is well equipped with defensive weaponry as a result of the many relatively recent conflicts: retractable point defense phasers to shooting down projectiles and small craft, retractable phased energy turrets for anti-fighter defense, and banks of multiple phasers, which was inspired by the multiple phaser banks used by Starfleet vessels in the TOS and TMP eras. If one section of the hull is heavily damaged, the other nearby phaser arrays can still function in circumstances where long phaser strips wouldn't. I used color pencils on the impulse drives, weapon warning strip marks, and the warp grilles to liven things up.
The main deflector was inspired by ST Renaissances's Phoenix class.
Both hull sections are capable of quantum slipstream and standard warp, as well as landing, which the wings are meant to assist. I place the Gypsy around 2425, when I predict that the conflicts with the Klingons and Undine will have run it's course, and by then, Starfleet will have begun getting back towards exploring.
In my vision of the ST Universe, Atolm's design that the Gypsy was inspired by only remained a concept, due to further analysis revealing that the design was unsafe, relatively soon before the Federation Council approved of her construction, and the name that was going to be used was instead used in the next Constitution class construction run. The plans for this design were found again by a designer browsing through the starship design archive, became an inspiration for a new design. That is not to say that there isn't a timeline where both were constructed though...
Whether or not the Gypsy will become a true successor of the Intrepid and her kin will remain to be seen...
Comments as always are welcome.
Now then, I see I have some catching up to do...