Robo3D enclosure with cheap board

I have inspired with Mike Kelly's enclosure but acrylic case method look expensive for it.
http://www.thingiverse.com/thing:681843
So I have used 4mm corrugated plastic and some ABS parts for joint.
Some my acrylic parts are narrow width but it can look into inside of it.
I can found joiner for corrugated plastic for gurde edge and extesion, but corner and edge joint has not been seen as existing parts.
So I have designed 2 parts for creation other parts are existing in market.

Result: