Here is a link to a mini Concrete crusher I found while looking threw an old Italian trade magazine i have. The link is from England so is in english. The machine is a Guidetti MF520 15,432 lbs, will crush 25 tons an hr, has an imput size 20"x24" and cost 98,353.00 US dollars. http://www.globalplant.co.uk/new_equip/mf520-1_mini_tracked_crusher.htm
That would work pretty good for onsite work. Although, I don't think that 25 tons/hr is really worth the cost.
I have seen a micro crusher working at a construction expo few years ago. fits on the back of a trailer with a micro digger as a set. Considered purchase but went in another direction. Cost was £16k so about $32k Took everything they could throw at it.
I would also agree
I wish I could find one of those to try out myself. Komatsu has or had a small crusher.