I bought a white iPod video (generation 5.5) a year or so ago. Recently it got leaked on by my windshield. As soon as I saw it, I took it apart, rinsed it in isopropyl alcohol, and dried it with compressed air. It worked for a while. The hard drive ended up being the problem. I wanted a THIN black 7th generation, so I bought the black 7g front, 7g frame, thin 7g back, 7g headphone jack/switch, thin 7g battery, and the black port bezel.
The 5.5g logic board and screen fits right into the 7g frame. The 5.5g click wheel fits just fine in the 7g front. The 7g battery powers the 5.5g logic board just fine. I haven't been able to see the headphone jack and hold switch functionality yet. I am waiting for my iFlash SATA to arrive, and then I will order an SSD.
A lot of these parts seem to be interchangeable through generations. Too bad they didn't apply any of this to their newer devices. I got angry with it when I couldn't get it to work, which ended up smashing the hard drive platters. The hard drive was toast anyway.