As a dedicated IKEA shopper and frequent purchaser of the $9.99 Lack side table, I'm annoyed I didn't think of this myself. By stacking and gluing together multiple tables, you can create a neat licorice allsort-like effect.
The example on IKEA Hackers attaches castors for portability, but you could also use shorter legs (or cut down those that come with the table). The key step is using wood glue so the individual layers don't separate. I'm definitely adding this to my weekend project list.
Liquorice Lack Table [IKEA Hackers]