I think chinese pride, along with the advances being trialed on the J-10 such as the diverterless inlet, make a T-50 purchase a low possibility. This is also making the fundamental assumption that the chinese won't leapfrog directly to 4.5 gen optionally manned fighters. It can be argued that 4/4.5 is the cutoff point before serious cost increases due to stealth are incurred. Going to high performance systems and materials to get raw performance, coupled with asymmetric thinking and going for the raw numbers approach is a potentially cheaper route to counter the US and Russia. More optical eyeballs in the sky, coupled with mesh radar networks of UAV's and UCAV's will mean the US will be forced to turn to missile hauling, but a limited stores capability (unless a missile truck like the B-1R or FB-22 come online) will mean losing against a numerically superior force.
Note that the last picture looks an awful lot like that all black chinese UCAV concept that was shown at a trade show.
I"m surprised in this day and age that semi-vertical stabilizers are still considered acceptable. I guess it must be a risk reduction factor at play, because an ICE style configuration with thrust vectoring and/or a fluidic nozzle would seem to be the next logical step, with an optionally manned cockpit block on an otherwise UCAV high G rated airframe.