So, just buying home routers and flashing them with third-party open source firmware wasn't enough, I started looking at "router boards". Router boards are low-cost power efficient computers usually with multiple network interfaces suitable for being used as firewalls or routers.
After some research, I decided to buy some alix2c0 boards directly from PC Engines. The alix2c0 is a basic router board model with two onboard network interfaces and two empty mini PCI slots suitable for wireless network cards. Other models of the ALIX boards have different combinations of network interfaces, onboard USB ports, and even form factors.
I also bought bright red cases designed just for the alix2c0, as well as wireless cards and CF cards. The red box at the left of the picture shows a fully assembled alix2c0 with one wireless LAN card (it's internal) and one external antenna connector (with no antenna attached). The board at the right of the picture is the plain alix2c0 board with nothing attached.
My OS of choice for the alix is m0n0wall. m0n0wall turns the ALIX box into a full feature firewall suitable for small businesses. One other thing that I use m0n0wall for is the hotspot voucher support, which turns an ALIX box into a standalone hotspot for use in Internet cafés or hotels. m0n0wall's internal hotspot support is still too primitive to support long term usage such as in an apartment complex, where the users may want to buy a ticket and use it for days or even weeks, and the hotspot would need to keep track of the usage.