Protect The Boss has exactly the type of female lead you're looking for! In fact the first time I saw her I found her so un-feminine I dropped it. But once I got past the first two episodes that everyone seems to have dropped, she turned out to be one of my favorite drama female leads. What's great about her is that she has a lot of COMMON. SENSE. Rare thing in dramaland. Unless I'm mistaken she cries once in the whole drama, and that's in front of a video of penguins falling from icebergs - who wouldn't? She's sort of like the female lead in I Hear Your Voice, but worse ;)
Reply 1997 is a really, really great drama - it's warm and funny and well-written. The female lead is not really a tomboy (she's a crazy fangirl) but she has a lot (LOT) of personality and is one of the quirkiest ones in dramaland. None of the characters in this drama fall into any stereotypes, so the friendships and the romance between the characters feel exceptionally real.
Last Cinderella (japanese): the female lead is definitely a tomboy (I think the drama starts with her imagining shaving off a beard or something weird like that). The plot may look a little silly on paper, but the characters are very human and endearing, so it's actually a good drama.
