Almost every motherboard manufacturer has jumped upon the SFF market after watching Shuttle's lead and for good reason; it breaks the traditional computer mold of being a plain beige box and gives a computer a bit of a flair stirring up a lot of consumer interest. The novelty of the SFF design also allows for higher margins with a board and case combo running in at close to the 300$ mark as opposed to some of the same motherboards coming in at under 100$. Neoseeker has a review for the Antec Aria case, you can read the reviews from:

http://www.neoseeker.com/Articles/Hardware/Reviews/antecaria/
Toaster-sized small form factor (SFF) PCs have invariably been "barebones" products that include the case, power supply and motherboard -- often cleverly integrated with unique design and features. They are the domain of motherboard makers who have driven the SFF market from its inception a few years ago. Antec's new Aria is probably not the first SFF case and power supply designed for use with any micro-ATX, flex-ATX or mini-ITX motherboard, but knowing the company's marketing track record in recent years, it will probably become the first widely successful one. There have been many small PC cases on the market in recent years, but mostly in slim form factor rather than the boxier toaster shape that Shuttle has promoted so successfully. You can read the review from silent PC Review (it's excellent, that swayed me into buying this case).

http://www.silentpcreview.com/article146-page1.html