Hi Pete!
Depending on which bolt-circle-diameter your crank has, Surly offers the following stainless chainrings:
Sizes: 94mm BCD x 30t, 31t, 32t, 33t, 34t, 35t and 36t
104mm BCD x 32t, 33t, 34t, 35t and 36t (nothing above 36T at this time)
110mm BCD x 34t, 35t, 36t, 38t, 39t, 40t, 42t, 44t, 46t, 47t, 48t, 49t and 50t
130mm BCD x 38t, 39t, 40t, 42t, 44t, 46t, 47t, 48t, 49t and 50t
Surly say...
Our 94bcd,104bcd and 110bcd x 34/35/36t chainrings are made with a 2.2-2.3mm thick stock plate and work best with 5-8 speed chains. Many folks are using these on 9 speed drivetrains but this can often results in a "tight fit" right out of the box (This will loosen up and shifting should improve after the chain breaks in). The 110bcd 38-50t and all 130bcd chainrings are machine finished to have a 2.1mm tooth thickness and thus work fine with 9spd chains.
Sadly, no 37T, Pete.
Best,
Dan. (who was once missing a few teeth himself, but now has them back...)