Heat output is the biggest concern, that's why you use fans! As for being low lumens, that may have been the case when the DIY's started out, but after seeing one in person I was truly amazed at the clarity and intensity of both color and light! Besides, the bulbs used for these setups are 33,000 lumens...hardly dim by any standard! I know some of the older and present "cheaper" setups want you to just use a TV and send that image through a fresnel lens, which will produce a far inferior image when compared to a the bulb's light directed through a 15" flat panel monitor then projected on the wall.
As for the cost of bulbs, they are about $50 per bulb and last about 20,000 hours. Plus everything you need can be bought from the above website, including tech support.
Either way I am exploring this option and will probably build one just for grins. If I decide to I will post here for all to see.
Some of the pics posted in their Project Gallery are just mind blowing! Here's one example
http://www.lumenlab.com/forums/index...=7739&st=0