We are absolutely aware of the Seamonkey project, although AFAIK it's only the continuation by other maintainers than before and not a rewrite at all. Mozilla also was written in C (on the lowest abstraction level). But as long as there seems to be no need and we don't have security support, we'll just remove it.

With the next generation of our Linux Workstations, which are planned to be based on Debian 4.0 Etch, Seamonkey will probably be available anyway since Etch includes Seamonkey or rather — due to license restrictions — the debranded version named Iceape.