Update: Now supports 3.x.x
Are you looking for a simple, honest, fast, mobile responsive opencart theme?
This one called 'iCart AM' might interest you.

As just mentioned, iCart AM is a fast, mobile responsive simple theme for opencart 2.x.x, the whole range.
Colour scheme is inspired by current Aston Martin racing colours, sort of.
There were two main focuses while developing the theme, Interactive UI and Performance. So all codes are minimalist.
Please visit the demo store here.
You shall see it's clean and without any extra information, but when you click on buttons it reveals more information and actions.
Speaking of clicks, effort has gone into making sure that user knows when he/she is doing something, clicking a button for example.
There are hover, click effects everywhere. For the tabs angle/caret indicator changes to suggest actions.
It supports product magnification also.

That's it really rest of it is quite simple and deault in behaviour. One might think it as Default theme pro version. It is compatible with with most modules including supermenu, blog manager things like that.
Please keep following the profile there are lot more coming.