I love cartoons from Disney, PBS, WB and obviously CN (haven't really found much interest in Nick though... yet). The cartoons I like are mostly geared toward kids and nope, they have little or no interest in any type of romance either. But being geared toward kids, it makes sense, since kids under the age of 10 are usually turned off by anything romantic, especially boys. So they're not going to put anything in there to turn their targeted audiences off. But they might have just the tiniest hints of romance just to keep the girls daydreaming, because, yeah, we girls really like that stuff.
And we liked it more as we got older. But boys, not so much. So unless a cartoon is for older kids, or specifically for little girls, I can understand why they don't want to put too much romance into them. They could potentially lose a lot of viewers.
I may not be clear as to how much "romance" you're referring to, but are you familiar with
Codename: KND at all? It's geared toward kids 10+, and has quite a bit of romantic relationships suggested (without it getting sexual). Numbah 4 (Wally) has a mad crush on Numbah 3 (Kuki), and, well, I'm a girl so I may be biased, but I find it really cute how he swoons over her, defends her, helps her, looks out for her, etc., but
refuses to admit he likes her, to ANYBODY. She likes him back, but is much more subtle. In the KND movie
Operation: Z.E.R.O. they FINALLY kiss each other (although they're not really themselves, but I don't want to give away too many spoilers), and it was really cute!
There's also another episode with a Numbah 19th Century and Numbah 86 (Fanny), and they have crushes on eachother, too, and also kiss toward the end of the episode. Numbah 5 (Abby) and her sister Cree have an interest in the same guy, and there are some interesting situations that arise with them, too. And Numbah 1 (Nigel) actually has a girlfriend named Lizzie, and they've also kissed a few times. So, anyway, the romance in KND might be similar to TT. That's one cartoon I know of that has some romance in it. But it's the only one I can really think of because, you're right, there aren't many out there. Not specifically for kids, anyway.