The best reference I can give is to the patent Albert Einstein got for an absorption refrigerator. A Wikipedia article is at this link: http://en.wikipedia.org/wiki/Einstein_refrigerator and it has a link to the original 1930 patent.

An analysis was done 10 years ago, which is at this link: http://www.me.gatech.edu/energy/andy_phd/index.html
but aside from a prototype, this did not result in any useful devices being manufactured.

At this time, there is a small market for absorption refrigerators for RVs and off-grid applications, but I have not seen where anyone has developed this technology into a heat pump for a building. I have done some rough calculations about the size of such a system, but I need to get some experimental data to feel confident about the performance parameters of such a system.

As far as cost goes, I think a unit for a small house could be made for under $1000. The components; solar collector, tubing, condensation vessel, duct work, and air handlers are all easily obtainable items and charging the system with the refrigerants is not technically challenging.

I am having a demonstration model with a collector area of .25 sq. m. fabricated (about 20"x20") and I am drawing up plans to put one on the roof of my house. If you know your seasonal heating and cooling needs, I can work up an estimate of the size of a system you would need.