insomuch as my gravel grinders are outfitted and used for overnight and touring trips.....
Trek 520 circa 2007,
Surly TravelersCheck circa 2010,
Origin8 CX700 circa 2013
(wouldn't ride this in a gravelgrinder race, but my go-to recreational gravelgrinder - sandsled bike of the moment.) My one bit of advice, from having done this for a while, is - Forget the "which knobby tire is ideal" dilemma. Simply choose fat, street oriented tires. I've been very happy with the performance of even straight street slicks on dirt - the 32c Bontrager Racelite slicks on gravel are very fast, very flat resistant, and suitable for finepack gravel, a little outgunned on washboard.