First of all you will need Xenon lamps with a DLP machine as well. In fact they will need to brighter than the ones you use on the same screen with film.
One buys Xenon lamps from their cinema supplier. My cinema supplier is American Cinema Equipment out of Portland OR. Their website is
http://www.cinequip.com/ . They even post their prices on the site. Another big cinema supplier is CPI their website is
http://www.cinprod.com/ but it isn't as informative as ACE's, you will have to call them. Fequently Box Office Magazine or Film Journal will publish a list of all of the cinema suppliers in the country and the world. Try
http://filmjournal.com/applications/guides/ for all of the addresses for all of the dealers in the country.