That sounds like a great idea, but you will still need a frame right? I don't mean to nitpick but I'm interested building one. A DIY tank is a great project but water is very heavy and the force of water pushing out is something to consider. Given my 55 center bar failure I think if I would do a DIY tank I'd be doing it in arcylic.Yeah, the internet is a handy thing! I'll make it from glass, held together with fish-safe silicon. The lid will be acrylic.
Stay safe and take care.