I go to the marketpro show in Richmond VA but its a long drive...last time I didnt buy anything, lol. I also sometimes go to the
http://www.supercomputersale.com/
To me, these sort of shows are ok, not great..you can get stuff like used monitors and some nice cases and also used systems if you are into them...like I have bought some Dell optiplexes at both shows. basically the stuff where you save some $$$ by not paying shipping costs.
The shows sometimes have a slight "seedy" feel to them, what with some of the dealers having a little "porn" section set up etc...aand some of them being the fast talking huckster types....an ounce too far over into a "carnival" atmosephere for my tastes.
But you can find some ok deals. I wouldnt have my heart set on any sort of "warranty". And do your homework before you go...otherwise its just to hard to remember prices of stuff....and you'll end up buying stuff from some dude you'll never see again at the same price you could have had it shipped to your door with a year warranty...so you have to sort of go in prepared with some purchases in mind. Scribble some prices on a sheet of paper and put it in your pocket etc.
And, yes, there are plenty of used laptops at both of those shows.
JP