Hi Thomas,
I think that what you're doing right now is fine -
"...linking from each content page to each other language domain, providing a link to the equivalent content in a separate language on a different CCTLD domain."
Seems sensible from a user perspective - I think the only potential downside is if you're implementing this using lots of anchor text - this could potentially be problematic.
Equally utilising javascript allow users to select language and location seems fine to me.
I hope this helps,
Hannah