[Tenkaichi]

Just thought I'd throw in my two cents.

Since all the romance that's occurred so far hasn't been in the focus of the show, I agree with the speculation that if we get anything close to a canon pairing, it's either going to be at the very end of StrikerS or in the manga.

Also, not that *main* characters can't hook up with not-so-focused-on-past main characters, but unless the producers stick Yuuno in a more prominent position, it feels less and less likely that NxY pair up. In this series so far, the parings have been rather even in terms of what type of cast they are -

Chrono and Amy - work together, more like supporting characters.
Erio and Caro, Subaru and Tiana - fit in the newbies catagory. They have the most interaction with their respective partner (or at least spring out the most emotions anime-wise for now)
Nanoha and Fate - almost the default pairing due to very close friendship.

Hayate and her knights - wouldn't say it's romantic per se, but for the sake of discussion, they're all typically grouped together.

Now if we were to use this silly train of thought, Yuuno would be paired with Arf in terms of casting, and YES, I know he's not a familiar. But like I said - casting-wise that would make Arf about the equivalent. Only evidence for throwing those two together post A's would be in the StrikerS 01 manga where we first see Arf in a chibi form helping Yuuno out in the library. Otherwise, the two have been grouped together for their support abilities.