I once saw an application of a solved case of the inverse Galois problem.
It is well known, that the Dedekind $\zeta$-function of a number field does not determine the number field up to isomorphy. In the talk it was shown that the $\zeta$-function together with a certain number of twists by characters do determine the number field. Let $K$ be the number field in question, $L$ be its normal closure. To define the right twist an abelian extension $M$ of $K$ was considered, which is as independent from $L$ as possible, that is, the Galois group of the normal closure of $M$ is a wreath product of the Galois group of $L$ and a cyclic group. The existence of such an $M$ is a special case of the inverse Galois problem, which had been solved before.
Sorry, but I have no name or further detail.