Does pokemon special manga end at Black/White arc???

Actually, they do have a Black and White arc. As for if it's gonna be the last, nobody can say for sure, it depends on the producers.

I believe Hidenori and Yamamoto are going to keep doing it until the games stop.

Pokemon Special is based off the videogames. When the games stop, so will the series.

No I don't think so,since it's said that the manga is based off of the video game,which leads me to believe the manga will stop,when they stop making pokemon video games..which I hope isn't anytime soon.