Yes, he's been shown in the anime.
He also takes up pretty much half of the new opening.
Please, there's no way Reborn could go to Adult Swim. Even the "childish" anime series they air like Inuyasha and Bleach have a lot of blood and inappropriate content at some points that legitimize their presence, but the Reborn anime has almost none of that, and the instances that do occur are easily edited. The anime has already done most of the necessary censoring for Toonami, with Reborn's green gun and toned down violence and stuff. In addition, though I like the anime, you can't deny the aura of childishness the series gives off, especially during the Daily Life episodes and the scenes with young Lambo. Unless they do a Shin-chan style dub with it (which I imagine would piss off a lot of people), there's no way it would work on Adult Swim.
And Tsuna in boxers is hardly as issue. Concerning his tendency to be shot by Reborn, the anime clearly shows the bullet turning into a ball of light before hitting him, but it could still be a problem. However, the biggest problem is definitely the mafia thing. Everything else would work more or less unchanged on Toonami.
The real problem is whether or not Toonami would last long enough until Reborn is dubbed.
Hmm, it seems the Reborn anime is going into filler with 84. It seems to involve Haru going onto the surface, where she gets attacked by a guy with a bee box of the lightning attribute and has to be saved by Bianchi. Well, I suppose the anime is only about thirty chapters behind the manga, so they have to put filler somewhere, and better here than the attack on the base, I guess. Any responses? "Filler? DO NOT WANT"? "The anime sucks anyway, so who cares?"? "It can't be any worse than the canon material"? "Future arc + filler = ultimate failure"? "Eh, it doesn't really matter"? "Yay, filler! Now we can see the other characters in this arc do something!"? Something along one of those lines?
So I was right all along that the fillers before a major arc is always 8 episodes (it was like that before the Varia Arc)?
Anyway, I watched episode 68 and 69, they were pretty good, especially for a filler (that wedding one was hilarious)
All of those episodes were canon, along with the episodes before the Varia arc. It's just that they happened way earlier in the manga.