A couple of months back I relayed the announcement of the Smach Zero portable steam machine planned by a small company. They were at the GamesCom 2015 and announced the final price for their Smach Zero handheld console. The shipment date has been updated to Q4 2016, so it is still a long way because you can have one in your hands. Pre-orders will start on November 10th this year directly on their website.
You may want to look at our previous article to check out the specs that were already confirmed a while ago. Which such specs you should be able to run games like Civ 5 and DOTA2 without too much problem on the go.