What tiny computer without screen nor keyboard to choose for a cyclist?

I am cycling to work, and I'd like to bring my computer with me, but I do not need the screen nor the keyboard, as they are available on-site.

I was thinking of odroid-c2 or something similar, but mali video driver is horrendously bad on my 1920x1600 screens. Also, xrandr does not work with closed-source mali drivers, so multi-screen setups are not possible.

Are there RaspberryPi-sized computers with ~4Gb of RAM, eMMC or better and with decent 2D performance on a mainline kernel?