Saw these elsewhere on the web (or maybe Dakka) and just wanted to post a link to some really cheap/cool crate options.
http://www.reallyusefulproducts.co.uk/usa/html/onlineshop/rub/b00_14litre.php
Saw these at Staples (USA) for only $1.00 each. Turn them upside down and you have a great little futuristic crate!
The bottoms have a raised hexagon pattern and the little handles can be removed quite easily.
There is a brand logo on one side (Really Useful Boxes) that could be covered up with a bit of plasticard and there is some writing on the hex-bottom that you may want to cover as well.
Things like the recycle symbol, country of origin, etc.
Perfect for adding cover and they'd look great with just a hit of primer and paint!