Imperative has a very strong expressive power in Turkish. Using 3rd person imperative in the right place can save many words.

Oğlunun kemiklerinin olsun bulunmasını isteyen Berfo Nine, "Ölunce oğlumla yanyana yatmak istiyorum" diye konuştu. ´Berfo Nine who wants to find her son  -  even if it was his bones  -  said: "When I die I want to lie next to my son".´

olsun has found its place in the middle of a possessive structure just like it was a disconnected addition or a quote from another, imagined sentence.

same meaning if you start like these:

Hiç olmazsa oğlunun kemiklerinin bulunmasını isteyen...

Hiç olmazsa oğlunun kemikleri bulunsun isteyen...

I had posted about it being used for condition (See post #8):

http://www.turkishclass.com/forumTitle_52268

Also

x olsun y olsun = be it x or y

Oh, that unlucky thread where I almost made a fight. How do you remember them all?

Isn´t there any colloquial tone in them?

Maybe

´No matter how much´.

Şimdi de yaşı kaç olursa olsun bu şarkıyı dinleyen herkesin aklına Ayla Dikmen´in adı geliyor.

Or for any question word:

qw olursa olsun = no matter qw

qw={ne, niye, neden, nasıl, nice, ne kadar, kim, kimin, kimi, kimde, kime, kimden, nerede, nereye, nereden, hangisi, kaçı, kaça, kaçıncısı...}

Düşüncelerimizin yönü bir olsun yeter.

It´s a noun clause!

I don´t think it functions as a noun here.

Rather it gives an "if" meaning (I had pointed out it sometimes gives an "if" meaning):

Düşüncelerimizin yönü bir olsun yeter. = It´s enough if our thoughts are in the same direction.

You mean

Düşüncelerimizin yönü bir olsun

is a kind of subclause and the subject of the main clause is a dropped pronoun. Ok, I guess a native ear can hear that better even though I can’t see any objection for interpreting it as the subject. Stranger things happen.

Btw, I have been talking here about sg 3^rd person imperatives even though many of the sentences in the thread including this are actually examples of subjunctive. (I found out just today.) The old subjunctive –e in sg 3^rd hardly shows any more but an imperative-looking form has taken its place. Even the meaning makes better sense this way.

Yes exactly! It cannot be interpreted as the subject.

We have two clauses here:

Main clause: yeter = it´s enough (its subject is "it")

Subordinate clause: Düşüncelerimizin yönü bir olsun = if our toughts are in the same direction or if only our thoughts were in the same direction, etc.

Hayatinda bir kez olsun Gülenyüz kullandın mı?  -  ´did you ever/even once...´

It sounds even more funny in a negative sentence:

Bir defa olsun sana hakaret etmedim.  -  ´not even once´

Turgut nasıl bilsin ki? ´How on earth should Turgut know?´

...Süleiman diye bir memur var ama onun da soyadı Yurttut. O olmasın sakın?

´Are you sure it couldn´t be him?´

abla yoksa sen tutunamayanlar kitabını mı okuyorsun??

kızı babasından isteyelim babası yok ki baba olsun birinden isteyelim

Something like ´let us ask the girl´s hand from her father she does not have a father ok let us ask someone who acts as her father´.

The funny thing here is

                                     [baba olsun] bir|i|n|den

is a compound. Besides it seems to be a noun compound lol.