According to Digitimes sources, Microsoft will officially launch Windows Mobile 6.5 on October 1st, 2009. Shortly after, in February 2010, Microsoft will release an upgrade version with an improved touch interface.
The same article reports that Microsoft will launch Windows Mobile 7 in Q4 2010, later than expected. Rather than retiring Windows Mobile 6.5 at that point, Microsoft will offer both versions with 6.5 being aimed at budget devices and Windows 7 at more advanced devices.
It appears that Microsoft has opted for a two operating system strategy to take on competitors such as Google Android and the Apple iPhone OS. Maybe those leaked system requirements will in fact be minimum requirements, explaining why Microsoft will need Windows Mobile 6.5 for the budget market.