Actually, you are both wrong, it is Neogonodactylus wennerae. It is a gonodactylid, however, not a Haptosquillid (Protosquillid). Tampa Bay does sell does sell N. wennerae. I just received a shipment of a couple dozen adults including several nice orange females. Several have alrealy laid eggs.
It is extremely rare that an Odontodactylus scyllarus show up under 2 inches. They settle out of the plankton at about 1.5 inches and don't have good coloration until after a couple molts. At this size they are very difficult to find and collectors are not likely to see them - and even if they do, they probably won't bother collecting them. At 2-2.5 inches, O. s. do grow very quickly and I agree, this is probably not a good choce for a 7 gallon tank unless you are prepared to move it in four to six months. I would never deem to tell you what you want, but I will tell you what you are unlikely to find and what may not be suitable for the conditions you propose to house the animal in.
There are quite a few stomatopods in the 2 inch range coming into the Bay Area right now. Last week in the East Bay I saw several H. stoliura, G. viridis, G. chriagra, G. smithii and P. ciliata all in that size range. The last I heard, a couple of the G. smithii were still in Berkeley.
Roy