SyncUp is a yet another tiny tool that updates multiple repositories (Git and Mercurial).
SyncUp is unlikely to be of interest to many, so it's not currently published to NPM.
To install from Git:
git clone git://github.com/michaelklishin/syncup.git
cd syncup
npm install
npm link
Usage:
sync-up [path to directory with DVCS repositories]
(c) Michael Klishin, 2013
Released under the MIT license.