I want my software to run on LinuxMCE but it isn't open source
LinuxMCE can work with non-OSS programs, they must simply communicate via the DCE protocol. We do not have any non-free package hosting, but we use conventional debian repositories. You can not link a closed source application to GPL libraries, but you can implement your own versions of any libraries you need or contact Pluto which also have compatible libraries. We started as a fork off Pluto's own distribution and only have access to the code under the open source licenses. The code from various sources and we only have copyrights on some changes we've made. All of the core libraries that allow you to create a proprietary LinuxMCE "Device" without writing your own DCE communications libraries were written by Pluto and you need to contact them if you want these under a different license.
We make a conscious effort to maintain compatibility with Pluto's software so that we can communicate with commercial products employing their software. This means that if we make any changes to the communications protocols we make every effort to maintain backwards compatibility and we let Pluto use the changes to these core modules in an unrestricted manner.