We have created a model, inspired from RETScreen (see www.retscreen.net) to evaluate the economic viability of EVs. The version below (customized for Telsa Model S) is still a beta version, but we would welcome any feedback. The model is designed for international users so we have not fully implemented the imperial system yet (miles, mpg...) so for now, you may have to do some manual conversions from the SI (System of International Units). The model allow the users to take into account O & M costs, salvage value of the batteries, and allows for custom input of most important parameters. The next version will have build in Sensitivity Analysis.
You can download it for free at http://cleanenergyinstitute.net/public/EVScreen/EVScreen3.44Tesla.xlsx
Director, Clean Energy Institute of GPEKS