I forgot to add that I have all the tbz2 tarball with the sources files. I made a little script to populate /var/db/pkg/cat/pkg, remain the specific files related to each pkg.
I'm thinking of using ebuild helper with a little script which could decompress the tbz2 to D and then make ebuild merge again. I have the portage tree of the lost db/pkg. So it's doable.
