I don't know about the rtkernel, but there is a new version 3 beta, just been released, it now is solely based on Debian, & uses a Gnome or XFCE DE. The whole distro has been rebuilt, & is now modular, which is highly likely due to the MKDistro app' which inspired the creation of DL.

One of DL's goals is to be as simple as possible to use. It is highly influenced by OS X.

Have a look at their web site? If you have I just wasted my time... :-)