The president of HK-USA mentioned in an interview that H&K has sold a license to Umarex for the production of .22 LR rifles patterned and branded after the H&K 416, MP5 and MP7. From HKPRO forums:
.22's: HK has licensed Umarex to produce .22-cal versions of the 416, MP5, and MP7. At least some of these should be on display by SHOT Show in January 2010. It has not yet been determined which models will be released first.
At this years SHOT Show Umarex unveiled a licensed rifle patterned after and branded the Colt M4.
Colt and Umarex have teamed up to produce the Colt M4 .22 Tactical Rimfire. The is probably the only real “Colt M4″ you will ever be allowed to own!
I am not 100% sure they are in fact AR-15s. UMAREX USA uses well known brand-names such as Beretta, Ruger and Walther to sell their airguns. This could easily be a AR-15 patterned rifle much like the .22 GSG MP5 or GSG AK.

There will be four different models.
Colt M4 Carbine
* 16″ Barrel
* M4 collapsible style stock
* A4 flat top upper recoever
* detachable carry handle
* A2 flash hider
* A2 pistol grip
* 30 round magazine
* Weight: 5.95 lbs
Colt M4 OPS (includes the following extras):
* Rear BUIS (Backup iron sight)
* Free floated aluminum picatinny rail handguard
Colt M16 (includes the following extras):
* 20″ barrel
Colt M16 SPR (includes the following extras):
* 20″ barrel
* Free floated aluminum picatinny rail handguard
* Flip up read and front sights

Fake suppressors will also be available as seen in the above photo.
It will be officially announced at SHOT Show 2009.
Hat Tip: OnPointFirearms