There is a new version of viking. I've just copied the 1.4.1 ebuild, changed archiver from gz to bz2 and it seems to be working here (amd64)
viking 1.5.1 is out now. Only change needed in the ebuild was to change the download file type, it is now bz2. It also seems from the NEWS file that viking has optional support for using bz2 to read compressed files. I could not see any map tiles with viking 1.4.1, but viking 1.5.1 worked as expected (I tested with the openstreetmap MapQuest source).
ping. If needed I can also update the version in the tree.
@graaff please go ahead and add yourself as the maintainer if you want. I haven't touched this package for a long time and are no longer interested in maintaining it.
I've added myself as maintainer and viking 1.5.1 is now in the tree.