This is a sequel to an earlier question about Alejandro Rivero's correspondence, the "super-bootstrap".
The correspondence itself was introduced in his "Supersymmetry with composite bosons"; see the tables on page 3. Briefly, we consider all possible pairings of quarks and antiquarks, but only from the first five flavors, "because" the top quark decays too quickly to hadronize. If we add up the electric charges, we get exactly the right number of combinations to get all six flavors of quark and all three charged leptons. There are also enough combinations to match all three neutral leptons (with an extra state left over); and there are also some exotics with charge 4/3. One may repeat the exercise with the full electroweak quantum numbers and it still works, more or less.
We seem to be getting back all the standard model fermions by pairing up five flavors of quark - except that two quarks should create a boson. So in addition we postulate that the standard model fermions are superpartners to these pairings: a lepton is a "mesino", a quark is (or mixes with) a "diquarkino". For months I've been thinking how to obtain this set of relationships within a supersymmetric theory. There are two problems: first, how do you get elementary and composite particles into the same superfield; second, what about gauginos, superpartners of the gauge bosons?
But it has finally occurred to me that maybe you don't need supersymmetry at all - you just need some extra fermionic preons. Suppose there are five fundamental quarks, udscb, and fermionic preons n, n',... which don't feel the strong force. And suppose that there is a new confining force, the ultrastrong force, and that udscb and n, n',... all feel it - they all have ultracolor charge. Then there will be "ultrahadrons", some of the form "qqnn..." or "qbar qnn..", and these can be the diquarkinos and mesinos of the correspondence. Leptons would be mesino-like ultrahadrons, the top quark would be a diquarkino-like ultrahadron, and the udscb quarks might also mix with other diquarkino ultrahadrons.
This seems like a very simple idea, and yet I see no sign of it in the literature on preon models. I would therefore be interested in any anticipation of the idea that does exist, and in any arguments which have a bearing on its viability.