Determinant of a generalized Vandermonde matrix
In general, there is a theoretical $O(n^{2.376})$ time algorithm for finding the LU decomposition of an arbitrary matrix using the Coppersmith–Winograd algorithm, which then obviously yields the determinant (adding $O(n)$ time).  There is a problem however that the Coppersmith–Winograd algorithm isn't considered usable in practice.  Afaik, people mostly use the $O(n^{2.807})$ time Strassen algorithm.  Doesn't Boost UBLAS's lu_factorize use this?

In you case, the Moore matrix should admit considerable optimizations because basically any Gaussian elimination like procedure like LU decomposition can be done abstractly.  Indeed, you'll find a nice $O(n)$ formula for computing the Moore determinant referenced by wikipedia, which presumably one proves by simply working out the LU decomposition in general.