mhonarc replacement for lists.debian.org

Description of the project: lists.debian.org uses mhonarc to format its archive for the web. mhonarc has a number of drawbacks, like not being developed very active or being rusty in terms of code. The pure date based layout of the mboxes isn't also the best, an additional thread based view, a method for searching the archive more intelligent would also be a nice feature. So what we are looking for: