It's always a question where to put the required RC-components on a machine. I'm talking about things like the on/off switch, charge connector, etc. I want them accessible, but not visible. 
On this machine, they could all go underneath, but I'm thinking that there might be a lot of dust, dirt, braches, leaves, etc there, and also it's not that accessible on the underside.
So on this model, I opted to put them on top, but conceal them under a lid.
I'm mimicking the engine lid from the original:
And then underneath the lid, the control panel is located. It has:
 - The on/off switch
 - A battery voltage meter
 - A sound volume dial
The charge connectors are just a standard XT60 and a balancing connector that are accessible under the lid, not attached to the control panel.
The control panel stand also serves as the mount for the audio amplifier.
The amplifier is a 2x50w D-class amplifier. The volume control is a stereo logarithmic pot - A1k.
Ebay links:
 - Amplifier: 
http://www.ebay.com/itm/272163830096
 - Volume control: 
http://www.ebay.com/itm/331883285534
 - Voume cap: 
http://www.ebay.com/itm/221309764371
 - Voltage meter: 
http://www.ebay.com/itm/201546863361