OpenWrt "Chaos Calmer" 15.05 released

One option is to get a small SBC like these APU boards, and populate them with appropriate mini-PCIe wireless cards: http://www.pcengines.ch/apu1d.htm

That said, it's really hard to beat the TP-Link Archer C7 on price. I've been quite happy with these: I have four of them. OpenWRT works fine and serial requires minimal soldering skills to install. If going that route, be sure to get v2; I believe ath10k has some problems with version 1.