Some more thoughts, thinking back to the early Soviet programme.The docking of Cosmos 186 and 188 - unmanned Soyuz spacecraft - was on the latter's first circuit. Essentially the same for Cosmos 212 and 213. The 25 hours duration between launch and docking only came in with Soyuz 4 and 5.So we could possibly see the Chinese using a fast rendezvous with Tiangong 1??Of course, the Chinese might well choose something completely different, but I would be surprised if their launch to docking is more than about a day.
More pictures now emerging
http://info.ch.gongchang.com/c/zhuangbei/zhuanyongshebei/2011-05-05/326993.htmlandhttp://tech.gmw.cn/2011-04/09/content_1807803.htm
Shanghai Space Technology Academy finished design of commemorative philatelic enveloppes for Shenzhou-8 mission. Launch is explicitly quoted on the enveloppes for October and recovery for November.