I just stumbled upon this website. It covers B-24 variants that were equipped with nose turrets destined for the CBI-PTO theaters. Looks to be very comprehensive, with the variants arranged by version, block, and type of nose turret fitted, as well as photos of representative aircraft from each production batch. IIRC, B-24D's that were bound for the Pacific had tail turrets installed in the nose, as requested by General Kenney. Hope this will be of use for all you Liberator fanatics- some interesting and unusual modeling projects, I think.
Mike
http://www.usaaf-in-cbi.com/Liberator_ID/Liberator_ID.htm