g_hbond could count hbonds per residue
This has been requested on the mailing lists, and I once implemented this ad-hoc for analysis. Implementation is straightforward and I'll be happy to do it myself.
-res hbres.xvg Output, Opt. xvgr/xmgr file
Since there is a feature-freeze for 4.6 i'll make a patch for the master branch.