Solid state drives usually have a 2.5-inch case, except for when they are of the 1.8-inch variety, but there are form factors smaller than even that.
As it happens, mSATA and mini mSATA embedded solid state drives is precisely what Unigen Corporation is focusing on at the moment.
The company has formally launched the Unigen Model 2202, 2204 and 2512, which will begin shipping next month (August 2012).
2202 and 2512 are mSATA drives, while 2204 is a mini mSATA unit. Performance-wise, they can achieve sustained transfer speeds of 500 MB/s and 4K random read/write speeds of 60,000 IOPS.
For reference, mini mSATA drives are 10 times smaller, in volume, than 1.8-inch units and 20 times more compact than 2.5-inch.
Both MLC and SLC versions of the 2202, 2204 and 2512 will be available. Prices have yet to be disclosed.