Extremely unlikely. Brotherhood covered all of the material the manga had to offer. That's the reason it was made in the first place - to cover the manga completely, since the first series aired several years before the manga was completed and stopped following the manga fairly early on. So Brotherhood did exactly what it was supposed to do, and unless there's more FMA manga someday, the FMA anime is likely over for good. They probably won't keep going without the manga as a guide.
We do have the Brotherhood movie, The Sacred Star of Milos ( http://myanimelist.net/anime/9135 ), to look forward to, though. It's not a sequel (chronologically, it takes place around episode 20 of Brotherhood), but I guess it's better than nothing. Unfortunately, since it was just released in theaters (in Japan) in early July, it'll still be a while before it's available to watch online. It'll definitely show up online shortly after the Japanese DVD/Blu-ray release in a few months, and Funimation has already licensed it, so it'll only be a matter of time before they do an official English release, too.