I've found a script on Petr's page that goes most of the way to what I want when assigned to a shortcut:

script:var objs = moi.geometryDatabase.getSelectedObjects(); if ( objs.length > 0 ) { moi.ui.mainWindow.viewpanel.getViewport('3D').targetPt = objs.getBoundingBox().center; }

It requires a section and a shortcut key press - but I can live with that.