i have a wide frame with small bones. for adding mass, little gains look much more impressive. as for lifts. if you arent lifing ballistically, there shouldnt be a problem. someone mentioned punching a bag or bball or other sports, yeah, you might have a problem there but for weight training the only problem you might have with small bones is getting too strong too fast for them...but adaptation has a way of keeping you from outlifting your bone structural strength. ie, someone wont get too strong on their bicep curls that their wrists break.(hopefully)
its not so much the bones you have to worry about, its your joints.