You might be far better off getting one Custom made to your own specifications.
A good cabinet maker will be able to give you an estimate dependant on how much Glass/Lighting you want.
I\'d suggest looking at IKEA\'s website for Magiker as that is a good Cabinet for displaying miniatures and may help a cabinet maker cost up the materials and labour. http://www.ikea.co.uk
i go to estate sales and such.. you could also check with one of your local area schools and see if some of the students are willing to do a cupboard made to your specifications. being a teacher myself thats how i get some custom ones made at cost. hope this helps.