Take a look at the Scriabin Concerto in F# minor (1896) in three movements-- Allegro, Andante, and Allegro moderato.
It is lyrically neo-romantic in style, hauntingly beautiful, and puts demands on the pianist. It seems at once restrained, yet is very powerful in different ways at the same time. It's also not heard as much as it ought to be, so also meets your criterion of less commonly heard concertos. My sense is that it was somewhat over shadowed by the Rachmaninoff Concertos and Rhapsody. But it's a great concerto in its own right. Sometimes it makes a statement not to play a tired "war horse". Also, people enjoy hearing a wonderful work that is not overplayed. I think you'd like this concerto a lot.