Can be built on madbean aqua boy board. It simply a boss dm-2 with some value changes to make it a tad brighter. You can build either version on same board
Madbeans also has an Aquaboy Deluxe that adds modulation into the mix. And, yeah, like thewintersoldier said, they're solid boards with fantastic build docs.
Along with that, you could look up some of the schematics that are out there for the Aqua-Puss and compare them to the Aquaboy. Probably amounts to a few updates to some resistors and capacitors. My understanding is that the Madbeans one was based more on the Aqua-Puss than the Boss DM-2 anyways. Could start there. Here's a post I found about that very thing: