I've wondered about the effects of antiestrogens or estrogen blockers on skeletal growth in adolescent males. Growth plates naturally close in response to circulating estrogens, secondary to testosterone breakdown. It's basically one of the reasons AAS shouldn't be used in skeletally immature individuals. I suspect the process of physeal closure would be arrested by estrogen blockade. Any takers? 
Yeah, I'll take you on this one..... i think you probably are correct in your thinking about prepubescent humans. Antiestrogens are not something that should be messed with at that age because of the potential to mess up long bone growth by delaying physeal closure.
If you consider animals as a human model, its been proven that males that are castrated immaturely (or prepubescently to use human terms)--ie dogs or cats, or in one case I know of an African lion they all have elongated long bones relative to siblings that weren't castrated. Its very well documented in large breed dogs.
If you think about it, castration effectively removes the testosterone source in a male mammal. There is testosterone production by the adrenals, but in relative terms, the testosterone production won't be as significant as testicular production unless there is some sort of adrenal abnormality. Estrogen in mammals comes from either degradation of testosterone (like you mentioned) or from the adrenal gland. Even with adrenal production, without the higher levels of testosterone to degrade to estrogen being produced by the testicles, there won't be enough estrogen to influence the E receptorAlpha in the bone growth plate. As a result you see slightly delayed growth plate closure, resulting in longer long bones.
The lion I mentioned is probably the most stunning example of delayed physeal closure. He's fully 2 1/2 to 3 inches taller than any of his siblings and his father and tops out at almost 170 lbs heavier (he's carrying more body fat and less muscle mass than the other males because he is a castrated male) Because he was castrated as an immature male, he also doesn't have a mane, so from a distance he looks like the longest legged female lion I've ever seen.