The buffalo WZR-HP-G300NH [buffalotech.com] meets all of these requirements and ships with DD-WRT. However, as the last, very recent thread mentioned DD-WRT is not well maintained anymore. Your best bets are either TomatoUSB [tomatousb.org] or straightforward OpenWRT. I prefer openwrt because it allows simple configuration of hardware taged vlans. (from slashdot)