Hi,
I think you can try linear regression analysis in EErdas, ban but forget arcgis either for regression analysis or for markov, i think only andes can do this.
have try : change detection? it can be used in erdas/andes.
Idrisi made : LAND CHANGE MODELER SOFTWARE FOR ARCGIS : http://www.clarklabs.org/products/Land-Change-Modeler-Overview.cfm. have you tried it?
regards