Allow to asign multiple parents to a taxonomy term

[Atoon]

I think it will be nice to allow terms in hierachical taxonomies to have more than one parent.

There are no plans indicated for major changes to the taxonomy schema, which would be required for this. Suggesting wontfix.

I and a number of other WordPress users I know want the ability to assign multiple parents to a child category.

Perhaps major changes to the schema can be avoided by having the concept of a 'primary' parent category/taxonomy and then having a separate table/structure with the additional parent categories?

I am prepared to offer money to someone that is prepared to implement this support.

There are zero plans to change the term/taxonomy schema in the future. Additionally, even if there were minor adjustments, multiple parents completely destroy the concept of a hierarchy and would likely have absolutely zero traction from the core developers.

Multiple parents would result in a half-baked schema, UI, and changes to the taxonomy API for hierarchical taxonomies. It's just not going to happen.

Based on your proposed solution, a plugin could implement what you're looking for.

vlasky, what you're really asking for is many-to-many relationships between terms. This can be easily achieved with a non-hierarchical taxonomy plus an extra terms2terms table.