@siren, matse: thanks for the suggestions. the line between fanboyism and acceptable behavior in such cases is a bit thin. on the one hand, if i were part of the academic elite in the field access would be a given; the very fact that he doesn't know who i am, however, puts me in a grey area where it could be a good idea to try, but it is not that sure. the general idea is that these people are paid to answer questions from their own students, or to take questions in public events such as conferences. sending questions privately, eg through email, leaves them at liberty to either disregard the writer or not. i have had very different experiences through the years: for example, my recent research stay in America was a direct result of someone being willing to give me credit and space even if he could just have dismissed my request. he had absolutely no reason to think that he could get something out of my visit, so he basically wrote me a blank cheque, and it was a very good idea indeed in the sense that he ended up liking my work and we're now set to write a paper together. unfortunately, however, this is not the rule, and also while the guy in question has credibility in his field he's still at GMU, which is a good university but not top of the feeding chain. on the other hand, this person i'm thinking of writing to is at princeton, which basically means somewhere completely unaccessible, for the time being, for the likes of me. i guess i'll just have to try my luck, and if i end up being cast as a hapless kid and get no reply at least it won't be unexpected.