Well I broke some parts to my HM-601 so I'm deciding to make it a little project. I'm replacing the 755560 size, 600 MaH LiPo battery with another 755560 2700 MaH LiPo battery, hopefully giving it much more time on one charge. The front board pieces LiPo connector and power button switch have both broken off, so I'm trying to find out a solution to that, I'll try to solder and glue the pieces to them on and hope for the best.
For the chassis itself though, I'm unsure what to get or use for a chassis. Maybe buy an undrilled frontplace for the iPod classic and use an iPod backplate? I'm looking to make the 601 a nicer looking, smaller profile player now. I'll post pictures tomorrow morning of my work in progress.