1) How much to bring the utilities to the home? Electric, gas, water? What about sewer? Is there city sewer?
2) What kind of foundation...slab or raised house on piers?
3) Figure on paying around $150 per SF for the modular home. Watch out for the "options" packages...they can add considerably to the price.
4) Check on your insurance for the modular.
There is a modular home builder in Lexington,MS. Some names to investigate online are Safeway, New Era, Carolina Building Solutions, and Genesis.
A ball park idea on price is to estimate the coast of'stick built" and then realize that modular will cost more.
According to San Francisco Chronicle's August 5th article, the sky is the limit http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/08/05/
Maybe the land is more expensive here (or not), but sounds like you can get an ultra luxury home out of module home.
So, read the article about the pros and cons, get expert opinion and compare the manufaturers