Anything like "The virtuous Queen of Han?"

Does it matter to you if the love interest of the noble person also ends up being a noble person?

Like they were raised poor and separate, that's how the nobleman/woman meets them but you know they're of noble origin.

 Naiwen:

Nop, I've seen and loved dramas like Hong Gil Dong.

This is from memory but from what I remember:

Legend of Hua Mulan - I believe a prince of the 'enemy' nation falls in love with her. 

Queens of Diamonds and Hearts  - if you can stand Hong Kong comedies the emperor is forced to marry one girl and also marries another by his choosing. Neither one is noble.

Mirror of the Witch - exiled princess and I believe the guy is born to a noble father but a lowly woman so he can't inherit from his father.

Perfect Couple - she unintentionally replaces a noble woman about to marry a noble man.

Princess Agents  - a girl taken as a slave has half a dozen princes falling in love with her.

Ice Fantasy - this is more fantasy - immortal falls for human woman.

Fighter of the Destiny - another one with fantasy elements. Guy from middle of nowhere visits capital and he has a princess fall in love with him and a noble woman. He's destined for the noble woman.

Man Comes to Tang Dynasty - this is a bit different, a man travels back in time into the body of a noble man in an unhappy marriage with the daughter of a rich commoner. It's a comedy. 

Sungkyunkwan Scandal - she helps young noblemen who go to school cheat IIRC. At least one of them falls in love with her.

Love in the Moonlight - similar to Sungkyunkwan Scandal. She's helping people with romance problems and gets stuck in the palace as a eunuch. 

Moon Embracing the Sun - the prince falls in love with a shaman who reminds him of his childhood love.