Hacked on XDot, which uses PyGtk/Cairo and the xdot intermediate format and thus sidesteps the limitations I encoutered working on dotviewer. My changes are in a Git branch created with git-svn. Get it here:
git clone https://mg.pov.lt/xdot-mg.git
Try it out
cd xdot-mg ./xdot.py sample2.dot
See the changes
gitk --all
Overview:
- Supports more .dot features.
 - Nicer node rendering.
 - Animated jumping between nodes.
 - Highlights node/edge under mouse.
 - Ctrl-drag zooms.
 - Shift-drag zooms an area.
 - File open dialog.
 - Zoom-to-fit reacts to window resize.
 
I must admit that git is nicer than bzr to work with, but a bit of a pain when you want to publish or share your changes.
I will not be sprinting tomorrow.