consider a 'universal' mount in all cases (not a model specific mount) and keep
all the screws. This will give you the option of upgrading your entire projector
without a new mount 5-10 years from now.
$430 (rack rate price, a quote will be lower 5-10% depending on quanitity)
DLP, 800x, 2yr, $10 back from NEC at http://necstarstudent.com/