I got the colored acrylic from bouwplastics.nl (The Netherlands). But I suggest to just look for them on-line, there are lots of suppliers.
For the rest of the materials I surprisingly stumbled upon an on-line pet-shop. I suggest you do the same, there are lots of people making custom made cages for there animals and therefore these pet-shops have all the materials you need to make a nice aluminium enclosure yourself.