I'm absolutely smitten with all three of versions of Philip Wong's see-through Flow Radio for Lexon. It's a slightly larger than palm sized portable radio and MP3 amplifier (aka plug-in your device through the audio jack) with the minimalist's aesthetic in mind.
" The main goal in creating Flow was to design a minimalistic radio, limiting the design to the strict minimum. The idea was to offer the user the possibility to discover and understand the industrial design of the object by allowing, with the transparent casing, to see inside and see the composing elements." - Philip Wong
We'll have to wait a little while before Lexon brings the Flow to the US, but it's already available online in Europe for about $85.
Unfortunately, it doesn't look like the transparent BuTommaso Ceschi's Bulb-Sound-Speaker design went beyond the concept stage, but wireless screw-in LED speakers are available in less design dramatic form.
Speaking of dramatic, the Harman Kardon GLA-55 2.0 Speakers were some of the most beautiful design objects we've got to test. Although they're transparent, they're anything but invisible.
And if a DIY solution is more up your alley, here's how to convert canning jars into a pair of desktop audio speakers to get your jam on [groan].
(Images: as linked above)