Look around at Extron's website:
www.extron.com and find what you need. They have tons of professional grade products and they definitely make scalers/processors that output multiple formats to RGBHV.
Why not just run a video connection to the projector though? It is easy within a business environment to run wires down walls and such and you should be able to do it at a more reasonable price.
You may want to get in touch with an integration company that specializes in businesses or shoot me an email/PM if you want some specific information. There is a lot of engineering that goes into board rooms and office environments. Mounting, proper cabling, ventilation, audio, etc.
