you're not bothering me - if i can i like to help. Sorry for late response, i had some issues with my network.
http://www.mangago.me/read-manga/blue_sky_playground/
http://www.mangago.me/read-manga/arisa/
http://www.mangago.me/read-manga/mint_na_bokure/ (though this isn't my kind of art)
I'll try to remember sth more:)
i've got something more:
http://www.mangago.me/read-manga/asa_made_motto/
http://www.mangago.me/read-manga/the_one/
and of courese twins from http://www.mangago.me/read-manga/ouran_high_school_host_club/ (though they're not main protagonists)
(●'◡'●)ノ
first comming on my mind is:
http://www.mangago.me/read-manga/honey_x_honey_drops/ (but it's quite popular so there's a big chance that you've already read this)
http://www.mangago.me/read-manga/rhapsody_in_heaven/
and almost all of other Minami Kanam works...
http://www.mangago.me/read-manga/haou_airen/ (but the ending is bad)
but basically i don't think that shoujo goes well with action genre... You can try sth of this:
http://www.mangago.me/read-manga/private_prince/
http://www.mangago.me/read-manga/royal_seventeen/
http://www.mangago.me/read-manga/stroke_material/ (i find it quite funny and I like female character ^^)
If you go precisely for smut you can try katsumoto Kasane works (though mostly they're lacking in plot department;) or Yoshishara Yuki (bunch of them have funny/horny heroines).
Hmm....if you liked this & you are ok with smut & josei then you can try "Midnight Secretary". In this one they don't fall in love fast. Well...they actually do but didn't realize it till the middle of the manga. And still have to work it out till the end.
Again, if you are alright with smut you can try "Desire Climax". Warning: it's very smutty & mature. They don't fall in love fast BUT they had to work it out a LOT!! And at the end everything goes really well. One of the perfect shoujo out there.
Another one coming to my mind is "Black Bird". What can i say?! It's awesome. You just have to try it out. The couple goes through a lot in this one too.
Last but not the least, "Wild ones". Very very cute & long.

Please give me shoujo but one that fall in love fast... But that they have to work it thank you