Alienware has laptops with RX 470s in them but that's all I've heard about Polaris 10 in laptops.
"The AMD Radeon RX 480M (formerly known as R9 M480) is a
mobile high end graphics cards. It is based on the new Polaris architecture
(Polaris 11 chip) and manufactured in 14nm FinFET. Compared to the faster RX 490M, the M480 should be a slightly stripped down version based on the same chip. Up to now AMD only published benchmarks at the TDP of 35 Watt with 16 CUs. With these scores the card is slightly faster than a
Nvidia GeForce GTX 960M."
http://www.notebookcheck.net/AMD-Radeon-RX-480M.164291.0.html
AMD is still about a generation behind with FPS/W competing with Maxwell, not Pascal. EDIT: Or maybe not. If they really get that performance with 35W it will be significantly better than Maxwell.