OP, I answered you via PM, but I will re-post it here:
I’ve found only a few recent laptops have GK208 chipsets, including the VAIO Fit 14 w/ GT735m and these Toshiba models:
http://www.newegg.com/Product/Product.aspx?Item=N82E16834216539 – S55-A5274
http://www.newegg.com/Product/Product.aspx?Item=N82E16834216541 – S55-A5276
http://www.newegg.com/Product/Product.aspx?Item=N82E16834216601 – S55-A5279
If you’re actually getting any of the Toshiba ones above, go through NewEgg Business and use coupon code XB2BNew10 for 10% off.
I actually returned my S55-A5279 because it doesn’t support 4K displays, but it does have a GK208 card, and I posted the screenshot in the SM3.5 thread here: https://devtalk.nvidia.com/default/topic/546357/cuda-programming-and-performance/sounds-like-gk208-laptops-cards-will-support-most-sm_35-features
I ended up ordering a custom-built P50-ABT2G22 laptop with a 4200U CPU: http://www.toshibadirect.com/td/b2c/cdetland.to?poid=2000098991 that should also have GK208, considering the P50-AST2GX1 does: http://www.toshibadirect.com/td/b2c/pdet.to?poid=2000098506. The display spec on the P50-AST2GX1 are wrong though. That one actually comes with a 1080p display that can downscale to 1600x900 or 1366x768 and does support 4k displays.
If you want more details I wrote about my experiences here: http://forum.notebookreview.com/toshiba/724954-p50-review-3.html#post9332904
I ended up going with the one with the 4200U processor because I noticed it is very power efficient on another laptop I tried out in the Microsft Store even when subjected to load. I should be getting it early next week and I’ll post here with my experiences. Given the battery on these Toshiba laptops is a bit subpar compared to other brands, that also influenced my decision. Don’t get me wrong, the S55-A5279 gave me at least 3 hours on a charge, maybe 3.5 or 4 if I did reasonable power savings… just something for you to get an idea.