Originally it was assumed that all developers had access to x86 hardware, so there was no arch team created for x86. This is no longer the case, and x86 is to be treated like any other arch with regards to moving a package to stable.
If you want your application to be moved to stable on x86, please contact the x86 team. If your package requires specific hardware, or a specific non-trivial setup to test, then we will probably allow you to mark it stable, unless someone on the team can test it.
The following is a list of rules and expectations for members of the x86 team:
The x86 team can be contacted:
#gentoo-x86IRC channel on Freenode