To get an idea about the factors and parameters that are involved in land demand estimates, you may have a look at a document from the Government of Manitoba, Canada: 'Planning Resource Guide Calculating Supply and Demand for Residential Lands' , http://www.gov.mb.ca/ia/plups/pdf/sd.pdf
There are also different spatially explicit models, for instance cellular automata, agent based models, etc., to model land-use dynamics.
See, e.g., CLUE-S , doi:10.1007/s00267-002-2630-x or METRONAMICA, http://dx.doi.org/10.1016/j.envsoft.2011.09.005
Thanks Max. I used both Idrisi Land change modeler and DynaCLUE for my modeling. However, both do not include the demand calculation with projected population. However, DynaCLUE suggests using system dynamic model for its non spatial part and calculate land demand based on population growth. I am trying a system dynamic model using STELLA now. Thanks for your reply and the links. As I observed, most of these land use models provide spatial land allocations for the given land demands. I am still trying to find other methods to calculate land demand based on spatial as well as non spatial inputs of population growth and projected population.