The most valuable thing about a MBA degree is the networking with classmates and the intellectual exchange with professors and classmates from different disciplines. In MBA degree, it is the interaction and the intellectural exchange that really counts. Hence, if you really want to get the benefits of a MBA degree, you should look for MBA degrees offered by HK universities. They have better professors and better student profiles. Also they would provide better interaction. If you need to work in the mainland, many of the HK universities have MBA courses offered in places like ShenZhen and Shanghai.
In addition, I strongly suggest you to avoid Chinese MBA. Most of the important high quality business publications and academic journals are published in English. Also, English is the language for the business world. You will get much more benefits by studying an English MBA.
For GMAT, you may ask the universities if they would waive the requirement in view of your long experience.
Otherwise, you may just buy a GMAT cracking book from Princeton Review (
http://www.amazon.com/Cracking-GMAT-CD-ROM-2006-Graduate/dp/0375764771). I use this book 7 years ago. Study for two weeks and just follow strictly the advices in the book and get 700 marks in GMAT.
Hope the above information is helpful.