This is a very cool project.
In my request :
I mentioned the Buffalo Airstation N300 as a good target because this device is only shipped with DD-WRT as standard and is widely available.
http://www.buffalotech.com/products/airstation-highpower-n300-open-source-dd-wrt-wireless-router
If a DD-WRT + Pi-Hole build was made specifically for that device it wouldn't be inconceivable that Buffalo would start shipping it with that build. Having a device available with Pi-Hole built in would be the lowest barrier to entry. e.g. the reason why windows is more pervasive than linux is because it comes with most PCs.
I don't know whether this router will be fully capable though.