nothing good is under 50

The New School of Northern Virginia (although the tuition is right around $40k)

Location, please.

Dominion Christian (Herndon) K-12, Classical Christian, May be full in 8th, though it's worth a shot.

Ideaventions (Reston) 1-12, GT. If student is extremely bright. Most years, half the class is national merit.

Basis Independent (McLean) K-12. Hard core academics.

Ambleside (McLean) K-8 Charlotte Mason. Very small, but 8th grade is nearly all girls, IIRC. Shakespeare plays.

Trinity Meadow View (Falls Church) 7-12 Christian.

Veritas Collegiate Academy (Arlington) K-12 Classical Christian.

Even schools that don’t officially have rolling admissions may be willing to take an out-of-cycle application if they have space. It’s worth reaching out to any school you’re interested in to ask.

Waldorf

Agree with PP. SSFS meets all your criteria—except that tuition is about 42k.

Sandy Springs

British School?

Not rolling admissions, but St Johns could fit that bill. Or one of the Catholic schools.

Where are you looking? VA? DC? MD? Are you open to a religious school?

Hi. title says it all. Disenchanted with kids' current middle school. Seeking something else. Should have looked sooner but we thought we'd be able to make it one more year (DD going into 8th) before spending more, that would allow us to have older DD graduate before DD13 enters high school with the more expensive tuition. DD is a straight A student but bored to tears where she is there has been a multi-year decline and recent developments at the school have been rough - two students have left midyear after yet another teacher departure. She has a lot of extracurricular activities she loves so we don't want to be buried with homework. Otherwise pretty flexible on size, approach, etc.