I have that same mold from the Daity Connection, it is meant for 4 Gallons of milk. I did make a few 2 gallon cheeses in it that came out like disks but were still nice 2Lbs. wheels.
Living in an apartment in the city and aging cheese in wine refrigerator I must resort to smaller molds. I looked at Kadova molds which I think are amazing but I find it disturbing that the small ones cost $50. I have been working with the mold from New England Cheesemaking that came with my initial hard cheese kit from way back when I just started making cheese - it is conical in shape so you can never place a follower in it because the diameter changes as it moves down. Your follower will be either too small - which will cause a depression in the center and a nasty raised lip, or too large - which will cause it to get stuck mid way through pressing (It's more like a Ricotta draining basket than a mold).
I just ordered a bunch of molds from an Israeli online store (probably can't read this but you can see the photos
http://www.home-cheese.com/shop/products-list.asp?CategoryID=44) specifically this one
http://www.home-cheese.com/shop/product-info.asp?ProductID=370 - is a 2.2 L / 75 Fl. Oz. 6" diameter, 7" high - which I am betting on. It's imported from Italy and the cost of 28 N.I.S is approx $7.50 so not bad at all. I will get them in about 10 days. I hope some of these will work out. In the meantime if you hear of any solution - please post it, I obviously have the same problem as you do.
Here is a photo in one of my other posts of a Tomme that was made out of 2 Gallons in the 7.5"x3.5" Tomme mold from the Dairy Connection
http://cheeseforum.org/forum/index.php?action=dlattach;topic=3442.0;attach=7899;image - it looked improportionally thin when I made it but cutting through it, the size made sense. It's almost the same proportions as the much larger wheel of Gruyère
http://images.travelpod.com/users/lovin_apples/1.1221363000.38-1.jpg