I don't know about a Muslim Cleric. However, President Ahmadinejad was not allowed to visit Ground Zero. This was partly for his sake (imagine the kind of security he would demand) and partly because of his anti-American bias. He probably wouldn't have anything positive to say about the event other than praise for the terrorists.
Well, Ahkmenijhad is a totally different story. Like, in another dimension.
He wasn't denied access because of his religion, but because of the things he's said about the US. I wouldn't want him there either.
But a highly esteemed Muslim. I personally can't think of anyone because I simply don't know enough about Islam. I know they don't have a "leader", but surely one living Cleric is respected by both sides of Islam... no? And if not, what about a Jewish Rabbi? Basically, a non-Christian is what I'm getting at here.
I would not say this country is majority Christian, but rather 'christian.' i.e. it is more of a tradition or culture than a deep-held belief in Jesus, etc. The majority of Americans are familiar with Christian traditions and therefore aren't bothered by them whereas Muslim culture is relatively foreign to us. It is more of a cultural issue than a religious one IMHO.
I think religion and culture are pretty much the same thing...