http://i50.tinypic.com/jpc7rd.jpg
Heavy Runabout (Sentinel Class)
Hull: 7,000
Shields: 2,000
Weapons Two Fore, One Aft
Crew: 5
BOFF Slots: 1 Ensign Engineering 1 Ensign Universal
Consoles: 1 Engineering, 1 Science, 1 Tactical
Turn Rate: 20
Impulse Modifier: .20
Description: With the ongoing war with the Klingon Empire, as well as conflict with the Romulan Star Empire and the True Way, less and less starships are available to guard convoys in hostile space. After several failures of fighter wings guarding convoys, the Starfleet Corps of Engineers have designed this small craft to better defend freighters. In addition to its layout it has been equipped with a Mirco-Photon Torpedo Launcher. Micro-Photon Launcher comes standard on the ship and has a firing arc of 55 degrees.
It has a bit more hull and shielding than the yellowstone, while less turn rate. After a couple hours of failing to get a concept of what i think it should look like i took to google and found it. So all credit for the concept art to Google Images. This runabout is about 50-60 meters long. i.e. Bigger than a yacht but smaller than the Oberth. I foresee this runabout as a Lieutenant Commander + but that is unprecedented.