interesting article about christianity in middle east
http://news.bbc.co.uk/2/hi/middle_east/4499668.stm

QATMAN
Your question about Qatari Christian or Christian Qatari

I think the standard form is Nationality + Religion.

If I am not sure I think about what is written in a reputable newspaper and the form seems to be: British Muslim - Indian Muslim but you may find examples to contradict this. For example Iranian Christian sounds better to me than Christian Iranian.

bye Orry