A Central Asian Union was proposed by Kazakhstan President Nursultan Nazarbaev on April 26, 2007, consisting of the five Central Asian republics of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The proposed Union would primarily deal with interstate border issues, trade, visa regimes, tourism, and security. If realized, the Central Asian Union would represent a counter-balance to the existing Russian-dominated Collective Security Organization and the China-led Shanghai Cooperation Organization.[1] In his proposal, the Kazakh President said:

"In the region, we share economic interest, cultural heritage, language, religion, and environmental challenges, and face common external threats. The founding fathers of the European Union could only wish they had so much in common. We should direct our efforts towards a closer economic integration, a common market and a single currency."

The Journal of Turkish Weekly, Accessed: June 15, 2007
JTW News - Kazakh President Proposes Central Asian Union on the EU Model

__________________

Seems like a good idea in principle, but those countries do actually vary quite a bit in terms of economic development and political freedom.

__________________
... I am surprised at your insolence in writing to me at all. You know, as I know, that I bought this constituency... may God's curse light upon you and may it make your women as open and as free to the excise officers as your wives and daughters have always been to me while I have represented your scoundrel corporation.
I have the honour to be... your obliged humble servant, Anthony Henley
- MPs reply to constituent, mid 1700s

It seems so. The level of authoritarianism isn't the same in all those countries, is it?

From the cultural side, I am too ignorant. How similar are those Turk cultures really?

Reasonably, they are all of pretty similar history. Kind of like the differences between Austria and Germany. Obviously there are some differences due to who is close to them (Khazakstan is the least Muslim as it's near Russia, for example) but they are quite similar. Not identical though, they were inhabited by different tribes in the past.

__________________
... I am surprised at your insolence in writing to me at all. You know, as I know, that I bought this constituency... may God's curse light upon you and may it make your women as open and as free to the excise officers as your wives and daughters have always been to me while I have represented your scoundrel corporation.
I have the honour to be... your obliged humble servant, Anthony Henley
- MPs reply to constituent, mid 1700s

Well, in fact they have urgently require to unit, because even after union completed, total GDP would be $240bln which is less than one third of Turkey's alone and it is an energy rich region between Russia and China.
This region was united under the name of Turkestan in the paste. These separate states today are the results of Divide & Rule policies of Russians that favored and encouraged tribal identities. In linguistic stance, Kazakh, Kyrgyz and Tatar languages are from Kipchak branch of Turkish while Turkish, Turkmen, and Azeri Languages are from Oghuz branch. Uzbeks and Uighurs of China speaks something between proto-turkic and oghuz branch. The member of same branches can talk each other without difficulty , inter branch conversations requires some practice.. There is already a huge academic effort under the "common language project" to eliminate the differences between languages.
I think and hope this would be a push for greater union which would include Turkey, Azerbaijan, plus some possible future states. Many existed and projected pipelines , railroad from Turkey till Central Asia (which is under construction), highways (some parts completed, some parts projected) , visa regimes (states are already lifting visa requirments) , military cooperations would be the infrastructure of greater union...

BTW, I also expect another union between United Korea and Japan and maybe Mongolia in middle term..

__________________

Well it seems than a union between those Turk states sounds at least possible.

But regarding Korea and Japan.... the hell will freeze before they are joining together in a Union...

S.Korea and Japan will both join ASEAN+3 in 2012...don't expect any EU type stuff, more like NAFTA type stuff.

Turkics were ride on horse in ancietnt times.in your singature,Turkic girls are in hot bikini.