In a new published rumor, it seems that Microsoft may be lifting Windows RT licensing restrictions in January of 2013. This would effectively open up the new operating system to additional OEMs for ARM-based tablets.
Due to the reportedly high licensing costs of licensing Windows RT ($85 per device), it seems like a bunch of hardware makers have opted out of licensing this OS.
At this point, the only companies that are definitely developing Windows RT devices are Asus and Microsoft. There have been rumors about Dell and HP but at this time, they remain rumors.
It will be interesting to see whether Microsoft will do more to get OEM’s behind this OS. I personally wouldn’t be shocked to see Microsoft lower or even suspend the licensing fee to get more OEM’s on board, at least in the short term.