I’m pretty sure this theme can be one of the best:
Both two have same features.
Here there is some example on bottom of the page: http://themes.framework-y.com/elon/sliders/
It can be easily updated for your need: full width and large item height. It’s simple to use but if you have problems I can create the page for you for about 15/20USD.
In short words you can show your portfolio post type items with a horizontal slider with right / left arrows and you can choose 8+ box styles and types.