I'm not going to go back and rehash the ordeal over length limits vs. minimums, but to say that the max limits help to keep the power systems that can be used in check (overpowering the hull will not usually result in success vs. matching the power system to the hull size) and helps to reduce the costs REQUIRED to be competitive... AND that there are many (most?) that believe that IF you can run a 22" hull in P-Sport and keep it on the water during a heat race for 1-mile... perhaps you deserve to win. In other words... not many are worried about heat racing a 34" vs 22" boats together... the larger boats will usually prevail. SAW and 2-Laps are another story.
For the general "Sport Hydro" rules, all that matters is that you follow the rules for the class. There is no list of "allowed" hulls, other than a few listed as examples with rear-shoes that are allowed.
It's the same as Nitro, with some additional dimensional specifications (65% Transom width rule, etc.)...
Should be pretty easy to build something that would fit...
Hope this helps.