Twelve years ago, the Rio Rancho Master Plan indicated that they would need a third high school by 2018 but that was when the community was growing by 1,000 + kids a year.
@ANR1 is correct, the district is not growing enough to warrant a new high school and while Rio Rancho and Cleveland might be operating at capacity, they can take care of minimal overcrowding with portables. I suspect that if Rio Rancho does anything, it will be opening an Early College High School like so many other districts have done before them. I do believe that RRPS owns a comprehensive high school site in the southern part of town in the event that they need it. I am not 100% sure about that.
APS might need another west side high school in 10 year or so and the master plan for the area around the new APS west side stadium has a high school site planned and I believe APS bought the land. It would be across from the APS stadium adjacent to where the district is building the new K-8 school. Development on the west side is doing well again after several years of stagnation. If APS does need a new west side high school, I believe it could be at the expense of an east side school, which are seeing declining enrollments. Which means, it could re-purpose an existing east side school into a magnet or some other type of facility like they almost did with Del Norte a few years before they renovated and rebuilt that school and that school would cease to exist as we know it today - just speculation on my part.
I would also keep my eye on the Santa Teresa area for a school 10-15 years in the future. There is quite a bit of residential platting and subdivisions going in in response to the Union Pacific yards and the associated development in the industrial parks and the new San Jeronimo community on the Mexican side. But I think it is still way off.
A few communities have or are in the reprocess of rebuilding their high schools - Deming, Lordsburg, Reserve, Capitan but these are not new. Only replacements for their current buildings.