Just think about the dimensions and the need for it to be clear ... The display domes used for dolls? And consider a terrarium or fish tank or really big glass jar.

If you don't mind having the case edges show, make or buy a 15x15x15 cube with glass sides.

Here is a link that might be useful: glass dome?

I wanted to display my Teddy Bear but everything I found was too expensive. I ended up using a plastic storage bag, think it is a blanket bag. I'm not happy with it but can't afford the one I'd like.

Thanks lazygardens, for the suggestion of the glass cube. I'd never heard of that before, but I found a place online that was only $32 for the components to build a 12x12 class cube.

lovemkitchen, I agree, those trophy boxes are outrageously priced.These were so reasonable. I expect to receive it next week! If you are still in the market, I'll let you know how it works out.

You could construct a clear display cube/box out of clear plastic. Two canidate materials are acrylic and polycarbonate (plexiglass). Look for replacement panels for storm and patio doors. Use compatible cements to glue it together.

A lazy start could be a fish tank, but you might not find one with an appropriate shape. Make a lid for the top.

It would be best if the enclosure was air tight to slow aging. Flood the interior with dry nitrogen gas and seal the box. Keep out of direct light, flourescence lamps and the new compact flourescent lights. If practical, store in a darkened space.