Lots of objects can be jury rigged into smartphone stands. But few are as cheap or easily adaptable as reader Dave S' plate stand turned phone dock. It's a cheap stand meant for fancy plates, found at almost any craft store.
As Dave illustrates, a small plate stand works well in both portrait or landscape modes, and fitting plugs isn't much of an issue, if you don't mind doing it yourself. Plate holders are universal enough to work well for mounting iPads to walls, too.
There's not much more to say, really — just consider it before springing for a phone-specific dock or stand. Thanks for the tip and photos, Dave S!