Sig have launched the Sig 552. It is a .22 Long Rifle version of the 5.56mm Sig 556, which in turn is a civilian clone of the Sig 550. Externally it looks identical to the Sig 556 Classic with the swiss-style folding stock and handguard.

From Sig:

The Look and Feel of the Classic SIG556 ™ in Affordable .22 Rifle SIG SAUER, Inc., the leading manufacturer of commercial, law enforcement, and military firearms fuels the demand for the legendary SIG556 performance but in an affordable .22 LR caliber with the new SIG522 semi-automatic rifle. Featuring SIG556 parts including a Swiss type folding stock and polymer forend on a durable metal receiver with integral Picatinny rail, and a Mini Red Dot sight. The SIG522 provides the avid sport shooter plenty of action on a classic military style platform that give the look, feel and dependability of our full size SIG556.

Specs:
Overall Length: 29.8 in
length w/Stock Collapsed: 29.1
Barrel Length: 17 in
Rifling: 1 in 7 in
Sight Radius: 14.4 in

The MSRP is $515.