What is the situation regarding multiple investments in China - are there still restrictions on the number of properties which can be purchased by a non chinese national?
I have purchased multiple properties with no problems. The government is trying to cool the property market in Beijing, which is going up 'like a bottle rocket', but in lots of other parts of the country the property market is quite subdued. I think that it's not so much that one is banned from multiple purchase, but that banks are not supposed to lend on multiple properties, or at least the LTV for successive purchases has to come right down.
Don't forget that Macau and Hong Kong are both parts of China where there are effectively
no restrictions on foreigners owning property at all, and where banks are more than happy to lend to foreigners, and there are no currency controls.
To answer the original question about hot property markets, well the likes of James Lang LaSalle, DTZ, CBRE, Savilles and other multinational property firms are constantly producing reports on the China property market. Personally I favour second and even third tier cities which are much less likely to be in a bubble right now, but I am not convinced that even BJ is really in a bubble because there are lots of jobs and lots of people want to live there. China has relatively few truly megacities, and it's pretty certain that BJ and Shanghai will continue to grow, and get wealthier for many decades.
Places like Qingdao, Huzhou, Suzhou, Tianjin, Wuxi, Dalian all have their enthusiasts. I am pretty sure that a property investment in any of them will produce a good return over a 10-year horizon.