I have a spare Asus DSL-N66U which don't have OpenWrt support and I don't want to use it any more with outdated stock firmware. If somebody would be willing to work on OpenWrt support for this router I would donate mine so that at least other people can enjoy this router with OpenWrt.
Welcome to the forum @calavera. I'm interested on this device, not sure if it worth the shipping from your country, I live in Spain.
I added support previously for bcm63xx routers. BTW this seems a BCM4706 SoC based device.
I'm not sure if you noticed it's DSL-N66U, not RT-N66U, because DSL is based on Ralink/MediaTek SoCs, not BCM4706 like RT, at least according to this http://en.techinfodepot.shoutwiki.com/wiki/ASUS_DSL-N66U. Would you be still interested knowing it's Ralink?
I got that aswell, probably not possible to flash openwrt on it.