Should marital status and its international characteristics be included in a CV/cover letter? This post is somehow related to a previous post on
extra-curricular activities.

My question is this. 
Beside standard extra academic activities (previous work, particular sport achievements, participation to student associations and the like), is it advisable to write in the CV or cover letter for a post-doc position the marital status, if the applicant thinks this information conveys positive characteristics about him/her?

Say, there is a Spaniard married to a Canadian, they live in Norway (where the Spaniard just obtained his/her PhD) and they are open to moving to another third country (i.e., a country where both of them are foreigners). In my eyes, the information about the marital status and citizenship of the two spouses is providing evidence for multiple positive non-academic characteristics of the applicant (the Spaniard), such as determination, stability and flexibility that are beyond average.

I have conflicting feelings. I see that this kind of information provides positive non-academic information about the applicant, but maybe who will be reading this information won't be paying enough attention or won't have the experience or empathy to understand the implications of having this type of family.
For US applications, you absolutely should not include such information, as it can make for awkward situations during the hiring process. 

For applications in other countries, you may mention such issues in the CV where appropriate. However, you should not mention it in a cover letter, where it will seem contrived, artificial, or "stretching." People reviewing your application will not read anything into the characteristics of your marriage.