  A class of non-canonical inflationary models is identified, where the
leading-order contribution to the non-Gaussianity of the curvature perturbation
is determined by the sound speed of the fluctuations in the inflaton field.
Included in this class of models is the effective action for multiple
coincident branes in the finite n limit. The action for this configuration is
determined using a powerful iterative technique, based upon the fundamental
representation of SU(2). In principle the upper bounds on the tensor-scalar
ratio that arise in the standard, single-brane DBI inflationary scenario can be
relaxed in such multi-brane configurations if a large and detectable
non-Gaussianity is generated. Moreover models with a small number of coincident
branes could generate a gravitational wave background that will be observable
to future experiments.
