This is why Xero will not advance any further, closed minds, Xero should be the hub of all your contact system as it is a necessity to enter data and they can do it as they have implemented gmail. But unfortunately they do not realise the rest of the world uses Macs and many other systems to promote our businesses. iCloud Contact sync has been done by a UK firm Cloudpipes but they charge like hundreds of dollars. The other elephant in the room is connection to Social Media. Here is my workflow: Get a customer call from a Google search, add their name and mobile to my Phone and sms them my address, bill them via Filemaker CRM, print or email them. Add them to Facebook as this is linked to my Phone. They way I want to do business. Get a customer call from a Google search or Facebook or Ebay, Phone and sms them my address from xero, Bill via Xero to email address and syncing their details to iCloud contacts, gmail, cpanel domain contacts, Facebook, Instagram, twitter, Etsy, Pinterest. This could be a zapier.com thing to sort.

I'm a mobile business so use my mobile a lot for all my customers addresses, so synching between would be fantastic and save loads of time and duplication. Somebody must be doing this somewhere?

yes please has this been done yet???

Yes please. Any updates on this function?

Complete agreement. Integration between iCloud Address Book required. Duplicating addresses is a waste of time and resources.