Apple appears to be readying for the launch of the white iPhone 4, according to a pair of new reports. 9 to 5 Mac, citing information from a Dutch source, claims the handset will launch on April 27, with limited stock at first. The report also claims that T-Mobile will have a one month exclusive on the long-awaited handset in the Netherlands, and that units are already arriving in stores, with embargo stickers on the packages that state “do…