Building a 5g with a 6 or 7g case parts, 5.5g firmware

[DavidMCMLXVIII]

Hello, I bought a 60gb iPod video 5g with 64mb of ram to put a iFlash - Dual SD adapter and 2x512 SD cards. I want to use a slim back cover and the black metal front of a 6 or 7g case. Will the logic board from the 5g fit in a 6 or 7g iPod Classic metal framework? If it works would you just buy a 6 or 7g Click Wheel, Wheel Button, and Thin Headphone Jack & Hold Switch? Also I am looking for a custom black 1tb back cover. All the ones I see on eBay are the thick covers. Do they make thin ones? What is the biggest battery you can fit in a thin case with a iFlash-Dual SD adapter? Where is the best place to get parts from? Finally are there still websites to get custom firmware from? Would like to add the 5.5g search feature and cover flow if possible. Most of the links on youtube don't work.
 
Thank You,
Dave
 
Sorry this post is so long "Its my first day"