I don't think it's fair to call the Mugen/AE/Kyosho cars "not purpose built electrics".
The motor and battery are exactly where they should be. No need to reinvent the wheel. Move the diff over a little to centralize the battery a little and a new chassis plate.
There's nothing worng with the simple Mugen ECO style setups. Sure it's close to a nitro car layout, but it works fine.
It seems like all the goofy corndog layouts get applauded as "designed specificly for electric from the ground up". (Tekno/Hotbodies/Serpent/Durango) Some of those look like giant AE B44's. I hated working on my B44. I passed up buying the Techno this week because I don't like my electronics so cramped. Less body and sidepod = more crash damage IME. The tight fit in the Serpent or Tekno is something I'd like to avoid.