This paper addresses the problem of statistical prediction of crosstalk in densely packed wire-bundles, with a large number of conductors. The wire-bundle is modeled as the cascade of equal-length, uniform multiconductor transmission lines, characterized by the same cross-section. Bundle non-uniformity is described via random permutation matrices that are used to describe wire-interchange at section-to-section junctions. The model allows high numerical efficiency, and permits consistent statistical estimation of parameters of interest, such as upper and lower bounds, mean value and variance. Model validity has been checked by means of experimental tests.