  We consider the harmonic superspaces associated to SU(2,2/N) superconformal
algebras. For arbitrary N, we show that massless representations, other than
the chiral ones, correspond to [N/2] ``elementary'' ultrashort analytic
superfields whose first component is a scalar in the k antisymmetric irrep of
SU(N) (k=1... [N/2]) with top spin $J_{\rm\scriptsize top}= (N/2-k/2,0)$. For
N=2n we analyze UIR's obtained by tensoring the self-conjugate ultrashort
multiplet $J_{\rm\scriptsize top}$= (n/2,0) and show that N-1 different basic
products give rise to all possible UIR's with residual shortening.
