Romance-Action Chinese Cartoons?
Off the top of my head I can recomend:
Eureka Seven has both (mecha-romance)
and has the MC and main love interest naturally develop their relationship (along with growing up as characters) within the 40-some episodes it has. Also don't go into the sequal expecting the same type of story otherwise you'll hate a mediocre anime.
Macross as a franchise is another mech-romance series which while it places emphasis on the music, the love triangles are okay. The one's I'd recomend are Macross Plus (great visuals and "mature" romance), Do You Remember Love (if you don't want to watch all 30-some episodes of the original series) and the Frontier Movies (for idols, visuals and MC choosing a gril)
Escaflowne is another mech series; however it's mostly a shoujo romance with mechs thrown in. The only problem with it is that it starts out strong and then drops in quality during the middle portion of the series before picking back up.
Unless you don't consider mecha as action, or also consider harems (Index, Strike the Blood, Tokyo Ravens) as romance these are some good Chinese cartoons.