Why not all sources are available like for DM2000?
Nobody needs it. For unices, distribution of source code is an evident demand. People may download, modify and compile sources to adapt the software for particular platforms and/or operation environments. For Windows, on the contrary, all systems are binary compatible. Another good reason - there's no developers interested in collaboration (at least, at the moment).
Very flexible by design. Again, somebody scarcely will want to change Delphi source code since DM2003 is totally programmable through OLE and ActiveX scripts. Scripting is very easy yet powerful; on the other hand, Delphi sources are too huge and too complex to be modified by the average programmer.
Not free by origin. In fact, one needs a commercial compiler to build Delphi application. So that, open-source Delphi applications are not "free" for all users - only for Delphi owners.
VCL Patches problem. DM2003 cannot be built without several important modifications of VCL units. However, redistribution of the VCL sources is prohibited by Borland license agreement. Moreover, DM2003 may be build only by D7.0 Professional (Enterprise) - other versions are not supported.
Sources are available! The core of DM2003, namely DM2003 graphic engine, is a set of VCL components available for free download with sources. Besides, all scripts and DHTML resources are installed with DM2003 itself.