We address the problem of automating 1) the analysis of existing similar model variants and 2) migrating them into a software product line. Our approach, named MoVa2PL, considers the identification of variability and commonality in model variants, as well as the extraction of a CVL-compliant Model-based Software Product Line (MSPL) from the features identified on these variants. MoVa2PL builds on a generic representation of models making it suitable to any MOF-based models. We apply our approach on variants of the open source ArgoUML UML modeling tool as well as on variants of an In-flight Entertainment System. Evaluation with these large and complex case studies contributed to show how our feature identification with structural constraints discovery and the MSPL generation process are implemented to make the approach valid (i.e., the extracted software product line can be used to regenerate all variants considered) and sound (i.e., derived variants which did not exist are at least structurally valid).