Dr Brant Faircloth has developed an Ultraconserved Element (UCE) probe set for arachnid phylogenetics. In collaboration with Brant, John McCormack & Rob Bryson, members of the Hedin lab (thank you Jim & Shahan!!!) tested this probe set on a diverse sample of arachnids, at multiple phylogenetic levels.  The results are remarkably promising.  A preprint can be found here.