Bless Florian Behrens for ContactsImEx (and Back2blaque for pointing it out to me). ContactsImEx allows you to easily export and import your BlackBerry 10 contacts as a large CSV spreadsheet or vCards. The vCard format even allows you to include contact photos since it uses v3 of the *.vcf standard. You can then use that information to edit contacts on your PC and them bring them back in and merge them. Personally I prefer to do this in Gmail but many users have asked for a way to pull this off that did not involve BlackBerry Link and Outlook.
Check out ContactsImEx free in BlackBerry World and make sure to thank Florian!