I've had some success building an image for the Raspberry Pi using Buildroot. WPE WebKit runs very smooth on my Pi3+.
Building WPE WebKit with Buildroot goes like this:
apt-get update
apt-get install git build-essential unzip bc mtools -y
git clone https://github.com/WebPlatformForEmbedded/buildroot.git
cd buildroot
make menuconfig
Now follow the instructions here to configure it so it creates an image: https://github.com/WebPlatformForEmbedded/WPEWebKit/issues/500#issuecomment-435590466
Continue with
make
Wait a few hours and you should have your image file read under buildroot/output/images/sdcard.img
Here's a video of my results: https://www.youtube.com/watch?v=_KsCrg0kyac
However, I would still like to see a binary for Raspbian, but nobody seems to be able to build one. Here's somebody who tried, but stopped half way: https://www.j1nx.nl/ict-matters/compiling-wpe-webkit-for-the-raspberrypi/