This could be done using distance matrices of alignments or likelihood scores of topologies. I would like to know if one topology is significantly less likely than another (maximum likelihood) topology.
ML: The Swofford-Olsen-Waddell-Hillis (SOWH) test implemented in the package SOWHAT uses parametric resampling to generate a null distribution of log-likelihoods from the data to be used for hypothesis testing. This seems like a strong approach.
BI: Bayes factors are very useful in model testing when applied correctly. However, when testing for a significant difference between the ML tree and an alternative hypothesis, posterior model probabilities are easier to calculate and interpret. Here are two supporting articles: