I have looked for B-24 Liberator ARF or kits and the only ones available are builders kits from these two providers. They also have the more popular B-17. Basically you might get a fusilage and a box of wood along with plans, but probably just a box of pre-cut wood parts that you have to assemble for $400-$600. If anyone knows different, let me know.
American Eagle
http://www.flyrcmodels.com/
Precision Cut Kits
http://www.precisioncutkits.com/instock.html