Short answer: No, mainly because many of the iPod's parts are OEM Apple parts and they haven't made new parts for the 3rd gen iPod in many years.
Your best bet would be to find a suitable iPod on ebay and restore it to "shiny brand new" condition. Disassemble it yourself; you basically want to gut it. Take the rear metal case and front plastic to a shop and have them polish them up. Send the rear case out for laser engraving and have them re-etch the Apple logo and such into the back. Clean the internals and reassemble. Yes, a larger drives can be installed and there are adapters to allow flash storage. Install a new battery, close it all up, and you're done.
Cost depends on how much work you can do. If you can do all the polishing and engraving yourself it will be cheaper. Assuming you're able to disassemble, buy parts, and reassemble, the only thing you'll have to send out for is polishing and engraving. Rough ballpark figure for a restoration including new battery and flash memory upgrade? Maybe...$200?
@ Steve Godun
I'm not much of a tweaker, but perhaps, I'm missing something: on this page with spare parts (iPod 3rd Generation)
one can buy virtually all necessary components to assemble a fully-functional iPod, including "shiny" front and back panels (as their descriptions state) as well as other "stuffing".
Why would I even need to buy a used unit, have back covers taken somewhere to have them polished, engraved, etc.?
I could understand buying original unit and upgrade it with what might be old/outdated (i.e. drive, battery, etc.) and external appearance, but your unequivocal "no" kinda threw me off..
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
0
I think he made that point because you said you wanted original parts. Most parts you will see are not original.
crwdns2934271:0crwdnd2934271:0 Idaho iRepair crwdne2934271:0