Retractable roof for Atrium

Hi,

We bought our Eichler last year.  The original owners put plexiglass or acrylic windows over the atrium (we live in an A-Frame model).  We've enjoyed the ability to cover and uncover the atrium, but to be honest, they're at the end of their lifespan.  Does anyone here have a retractable roof or similar solution that they like?  The last post I found on this topic was from '06, so I'd be interested in hearing more.

Thanks!