The Irish version of the iPhone remains a good deal, despite its cost, insists the head of O2 Ireland. The device will be unusually expensive in Ireland, costing €399 ($605) for the 8GB version or €499 ($757) for the 16GB one; the latter costs the equivalent of €430 in the UK, or €370 ($499) in the US. Subscribing to the cheapest possible 18-mont…