I am in the Information and Audio Visual Technologies department at The National Infantry Museum and Solider Center in Columbus, GA. We have a lighting solution I think may work for you. It is a Luxam 10-523-OD light generator. It has a 12volt 100watt MR16 (if I am not mistaking) bulb in the base until, from there it runs fiber optics out to your case. We use these for low light cases with books and such in them. Hope this helps, let me know if I can be of any more help.
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Benjamin Watson
Sr. Information & Audio Visual Technologies Specialist
National Infantry Museum Foundation
Columbus GA
706-685-5816 office
http://www.nationalinfantrymuseum.org