I just posted a new version of findMRCA. This function finds the most recent common ancestor (MRCA) for a set of taxa. Now it can instead (optionally) return the height above the root of the MRCA of a set of taxa.
This version is in a new phytools build (phytools 0.2-83), which many users will be able to download & install from source.
This update is mainly to address the need of a phytools user. The previous version worked fine, so far as I know.