interfaith construction

Studying scripture and doing theology are fascinating and complex enterprises. Often Christians are confronted with radical cultural differences between the world they live in and the world of the Bible. Questions without easy answers are typical. The simple fact is there are so many practical questions that arise in daily life to which the Bible simply does not directly speak. 

A friend recently asked for my input on this question and I've wrestled with it considerably. It is a question of faithful Christian ethics. Here it is,

If you were a Christian building contractor would you be opposed to building a Mosque, a Hindu Temple or a Synagogue?

Please keep all comments and responses respectful. While this is a hypothetical question it is based in reality, so please keep that in mind. Also, this is not about critiquing religions. This is a question of Christians being faithful to their story. 

Is it faithful for a Christian to build a Mosque? I think it is an especially interesting question considering all the recent debate about the ground-zero building project.