How about Bostons Soundwares, I heard them at Bernies they had a bunch of different colors, sounded way better than bose cubes, plus you wont need bass blockers... bernies had them mounted on the floor to show that are good at any angles, they projected well...
normally $100 each though and a little larger than 4x4x4 they are more like 5.5x5.5x5.5 and heavy for their size, but A4L has them on sale for $30 each !!!! not too shabby... they have espresso, white and black still in stock, my original thoughts were nice for a kitchen or bathroom, since they are indoor outdoor so moisture wont be an issue, where some normal speakers it would...
Good luck and welcome to the forum...
I cant think of anything that small that wouldn't need some sort of bass blocker and would sound decent, you figure a 4" cube may have a 2.75 driver in it, thats not going to make much for mids and lows, if any...