This is my version of a DIY electric long board, I am still perfecting it and tweaking things currently. I printed the ESC enclosure, battery enclosure and engine shield using wood/PLA filament. I designed the prints to be able to print on a small print bed and so that they wouldn't break when the board flexes. The battery enclosure is three pieces. The motor mount when printed in pla (100% infill) lasted me about 12 miles before breaking, I remade it in aluminum. The part "boltmt.stl" (used with 3/16 hardware) is used to put nuts into the sides of the ESC and battery enclosures to give them a clean look.
I am using a printed wheel pulley designed by user: JuniourPotato93, and it works great.
I will upload dimensions at a later date, but leave a comment if you have any questions or want me to tweak the dimensions of one of the parts for your needs.
The resource that I found most helpful by far when building the project and choosing all of the components is this Instructables by: CoolRextreme, http://www.instructables.com/id/DIY-Electric-Longboard/ It provides an excellent crash course on all the knowledge behind the individual components needed, helping anyone to make your own knowledgeable decisions when buying the components.
Update: added spreadsheet with Bill of Materials
Future Project Idea: Hoping to be able to make a cheaper and more portable electric longboard example using a Penny/Nickel board for a future project!
I recommend printing with infill from 50%-100% as these are structural parts.