I stand corrected, once you hit the limit in one direction you have to look at simultaneous up and down to rank the CPU throughput. TP-Link do seem to be helping keep all the prices down, there are several newer cheap new routers in the current table
http://www.smallnetbuilder.com/tools...76-total-simul
GPL source-code seems to be available - any 3rd party firmwares - I see OpenWRT ...?