Is there a way to provide self-hosted web-based forking of Mercurial repos like BitBucket/Kiln?

I'm currently using self-hosted SVN with Trac for a FOSS project, and am slowly moving to Mercurial. I've got HgWeb set up, so I can view the repository and check out over HTTP, but I'd like to be able to offer web-based branching a la BitBu开发者_JS百科cket, Kiln and the like.

My server already has PHP and Python installed. Python is already taking up enough memory, so I don't think it'll cope with Java as well.

I've found this question, but there isn't a good answer and I don't need the full BitBucket feature set (basically just branch/clone and pull requests). There's also this question but it mainly got answers about simple hosting through HgWeb. There are also other questions about BitBucket alternatives, but they focus on externally hosted options, and I want the control and integration with my existing Trac install.

So, are there any free options available that let my developer community make their own branches that they can check into so that I can easily pull from them to get changes into the Master repo?

Thanks.

Making an answer out of my comment, as Ry4an suggested.

In this answer, a system named RhodeCode is mentioned, which its official site describes as

Open source repository browser/management tool with a built in push/pull server, LDAP, permissions sytem and full text search.

It has web admin support, forks, and other server-side repo management. Even though it has no Trac integration, I myself consider it a better hosted option than hgweb which I use now.