I just discovered this discussion thread and am also intersted in the topic (a solution for integrating home automation into media-center)
I'm not an LMCE user (at least not yet) so I don't understand all the internal details of it, but I'm the programmer of linknx ( http://sourceforge.net/projects/linknx/
) and can perhaps help on some topics.
The EIB/KNX model is based on communication objects and group addresses. Each group address represent a functionality. Each communication object is able to send its value to at most one group address., but can receive value from zero, one or more group addresses. So that's not always a one-to-one relationship. In addition, each communication object has a collection of flags telling if it can transmit it's value on the bus, must update it's internal value if a new one is received from the bus, or answer to a read request coming from the bus.
All this behavior is part of the KNX object model but EIBD only implements the lowest protocol layer (send and receive READ, WRITE and READ_RESPONSE telegrams for group addresses). To fully implement the object model, we need an additional layer. That's one of the reasons why I developped linknx.
Additionally to this, linknx handle the conversion from the binary data format. Every communication object is configured in linknx with a name, group address to send to ( and potential additional group addresses to receive from), communication flags and its data-type (for decoding bus binary format to understandable text values).
All the configuration, reading and writing of object values to/from the bus can be done by connecting to linknx on a known tcp port and send/receive commands in XML format.
I suppose that a DCE router could easily be interfaced to it, but I don't have a clear view of what commands this DCE router must be able to send / receive. What are the limits of LMCE concerning home automation, how is the configuration (group addresses, flags, ...) stored in LMCE