Please create a new user group (trusteduser). AutopromoteOnce: 30days from the date of account creation, and 400 edits.
Discussion: here
Per T139246: Migrate local group names to WikimediaMessages and T230103: Systematize wgRestrictionLevels it is not recommended to invent a new protection level not used in other wiki. The protection level and user group should be named extendedconfirmed.
@DreamRimmer Imho, for what you're asking (since the sysops can add and remove the flag), it's better to create an editautopatrolprotected level. You can also create a policy in which it's specified that "autopatrol" flag is granted to users who meet certain requirements, for example, and in this way sysops can fully manage the flag assignment (also for the editing of semiprotected pages). I mean, why is a new userright and protection level needed, when first of all you could try to add a new protection level for a flag you currently have on your project (please consider also the number of active users on the project)? Thanks
A similar user group that exists on other wikis is extendedconfirmed too (which probably better fits the purpose). But, since it's withdrawn, just saying :).