The 'Too Sad To Separate' cup design was originally developed by Jung and Jang in 2006. Since then, designers have experimented with design quite a bit, and finally presented the latest version on the product at the Design September Brussels 2010.
Even thought it might be difficult to use as an actual mug, I believe the product has to be available for purchase to the wide public - simply because it is so beautiful.
Plus, if you have uninvited guests, you can always serve them tea in this thing...
Check out the full Joon and Jang portfolio.