Susan's option is common and natural - more so than your options - and especially in conversation. There is no UK/US variation on this issue.

This would also be very natural, informal and common in speech:

"That building over there - you can probably see its roof - is our church."

Interesting, what I most commonly hear where I am from is ¨He has written a book that I have forgotten the name of.¨ English teachers, is what I have put in quotes also grammatically correct?  Is it not standard?

All of those others sound kind of formal to me.  Although perhaps I just come from a place where grammar is not a priority.  I agree with Richard, I thought the first option the OP gave was more common than the other two. 

In general, most native speakers would say "The building whose the roof you can see over there is our church."

Using whose is correct (even though we might think it should only be used when referring to humans).

Furthermore, using whose is shorter and easier to speak.
Plus of which would sound much too formal (and possibly even pretentious) in spoken English (unless one was trying to use higher level English).

I think most native speakers would say, "The building you can see the roof of over there is our church."

Richard,

Have you made a typo? You wrote,  The building whose the roof you can see over there."  You didn't intend to write the word the after the word roof, did you?

Thank you, everyone! :)

The (1) is a corrected sentence by a native speaker from UK, and I felt it's a sophisticated wording, but I guess it's nevertheless formal. Maybe I am a little familiar with 'whose' in conversation because I'm always a foreigner when speaking English.

So, in conversation, 'whose' is less rigid than 'of which,' but all the same they are both formal and the common expressions are with or without 'that' or without relative clause. I think I got it correct.