Just to clarify - 30/11/09 (actually 22/11/09 but in practice 30/11/09) is the earliest y/e you can have if you want to use an ARD of 22/08/10, not the latest
There is nothing stopping you from having a y/e ending one day before your ARD if you so want
As regards the length of the accounting period, I think that there is no legal restriction on the length of accounting period. However you must still comply with the law in terms of the holding of an AGM, namely
First AGM must be within 18 months of incorporation
A set of accounts must be presented at the AGM which cannot predate the AGM by more than 9 months