The marketing for RND Power Solution's Sync & Charge Dock ($35) makes it sound pretty appealing. Coming with a Lightning plug built-in, it claims to be compatible with most cases, which is a rarity when it comes to docks. The round plastic holder comes with a removable insert, designed to be left on when no case is being used, and taken off when one is. Unfortunately, the housing around the plug is still surrounded by the same amount of plastic as…