Well yes, cinder blocks and plywood will hold the tank. But, is that the way you really want your tank displayed? If you want a DIY stand...get some measurements from your tanks base. Then go to your local Lowes/Home depot/etc. Speak to them about it, give them the measurements. let them know what you want to do.
They can do everything you need. Make the cuts for you, whatever you want. Going this route, you can use custom doors, color, everything. Yes, its going to be more expensive than putting your tank up on blocks...but I'd bet you will be happier with it.