Hello gentlemen,
A little hint and tip to increase place in your showcase.
I bought this one because it's very easy to increase and it's cheap:
http://www.ikea.com/fr/fr/catalog/products/10119206/So, in a "do ti yourself" shop, buy cleats (in french serre-cables) like this:

Place four of it like that to support glass shelves:

Buy four glass-shelves, 30 * 38,5 cm, width 3 mm (it's cheaper et strong enough).

So for about 100€, you'll have an efficient and beautiful showcase.

Hope to be useful.
Best regards.
Alain.