Here's a listing of banks for Las Vegas... http://yp.yahoo.com/py/ypResults.py?stp=...
Ok first find out the zipcode of Southwest Las Vegas NV.....then in the searchbar on yahoo homepage....type in "BANK" ....then hit the local button and put in that zipcode......VIOLA ....you have your list of banks.
Have you tried a specif Banks website? NV.GOV will not be able to provide that info. Also try using Mapquest. You can usually search for banks, schools, ect on that website.
try "YaHoo! Yellow Pages".