Not going to happen. Projectors need a very small point source and smaller the source, the better. The OMNI-MAX theater use a special short-arc xenon, which isn't too efficacious, but provides extremely high intensity near spherical beam that works real well with the optics. The lamp power is something in the teen kilowatts and cost as much as a new Ford Fiesta.
Actually I think something like the rectangular LED array shown above might work reasonably well behind the LCD panel in an LCD projector, if the size matched up with the LCD panel and if it was used with a low F-Ratio main lens like they use with CRT projectors.
However this type of direct illumination would pose some problems with matching the emitters for output and color, so the LED array would most likely have to be used with a light mixer box and diffuser, to get uniform brightness and color.
I would go with Rebel 100's to get the highest luminous efficiency in the most compact array.
15 well matched Rebel 100's driven at 500mA in a 3 x 5 array on a thick solid copper heatsink, close behind an efficient light box diffuser with the LCD panel immediately in front of the diffuser, would make a reasonable home theater system with less than 30 Watts of drive giving more than 2000 lamp lumens and probably at least 500 lumens out the front, with efficient low F-Ratio optics.
The total lamp side light output of 15 Rebel 100's driven as described above would approach the light output of an efficient 150 Watt Halogen projector lamp, or 15 to 20 watt HID, but would have much longer lamp life.
15 rebels at about $7.00 each would cost 105 dollars, which is still less than even one bulb change of the typical HID bulb, and this would hopefully be a one time expense.
DLP's on the other hand need a very well collimated light source because they are a reflective device, and the easiest way to get that collimated light is from a very small high intensity source like an arc or HID light and an aspheric collimator lens, just as you say.
it would take quite a lot of cree's to produce enough light. Im not going to say it cande be done but it would take serious design and very precise placement and the LA would be huge to house enough mirrors lenses and optics to get a convuling beam that was straight. Plus the color. I woudl bite the bullet and go for another HID light. they should havea long life though HID has one of the more durable light producing areas out of any leds win though.
