1. Replace the standard speaker with:
Use a “Flat speaker” for the speaker element. Which would negate the need (as well as manufacturing tooling) of the designs perforated perforated speaker surface.
I would require much less power usage than the classic style sound driver/speaker needs. Also it would be less weight, part count, total material usage compared to the classic part.

Links to flat speaker item:
http://www2.warwick.ac.uk/services/ventures/news/25_03_04/

http://www.warwickaudiotech.com/

2. Get rid of the old-school antenna.
Replace with integrated flat RF antenna array. like those used in cell phones. This too would reduce production/material cost requirements associated with a classic style built in wand type antenna. Another good feature of the flat antenna is the fact it can be molded into the surface of the cube face.

3. Replace the turn dial Radio controls with a set of 2 push button controls (“On/Off” and “Scan”) like those on those dollar store portable radios. This would reduce production/material cost requirements as well as make for more aesthetically pleasing.

4. With all those cost savings (aesthetic enhancing) modifications more money can be spent on integrating the best wattage output solar panel for this device to both function on (internal battery/capacitor) as well as charge the extra batteries with.