In some customer scenarios, we have had a need of being able to install multiple FIM-CM instances in one forest with multiple PKI solutions. Some documentation like the new IPD guide for FIM 2010 indicates that you can only have one instance per forest. However after having researched this a bit internally, I was informed that there should be no problem in having multiple separate FIM-CM instances in one forest and that it is fully supported.
Space for Claus Jespersen 