Yes, very easy to make! Can easily be cut with plunge saw and attached with silicone.
I would suggest 4-5mm acrylic or polycarbonate. 3 would probably work good as well. Especially if its polycarbonate. I have a few sheets. The holes can be cut with jigsaw or laser cutter.
Plastic can be order from Jan o Mattson, Bauhaus, Biltema and many other places!