I would say never! Why? Read here

Never, vita is doing ok despite great comp.

Wiiu comp has yet to even get going.

I would say that sometime this year. You are basing this on thinking the vita will go up or at least stay even with last year. And that the wii u will go down or barely go above what it did last year. The wii u is going to rise in a big way this year with its line of games it has this year. The vita will shrink with all major support gone even from Sony. Japanese games are not going to save it since most of the big games are still coming to 3ds.

If Sony fails to deliver either a 4G Vita or revive the system as a PlayStation Phone, the I would say whenever Zelda releases.

I dont care any more, as a Wii U fan, myself and many others have had to endure a lot of ridicule and negativity over sales, the same goes for Vita fans too. Now i just focus on the great games and experiences ive had/will have with the system, i love it and that's all that matters. Wii U and Vita fans enjoy your systems, because its pointless bickering and comparing sales over two underperforming devices.

If Vita is really that undertracked then maybe not this year. But some day probably.

Never?? you do know that higher numbers in every week that make for sure that it happen in the future xDDDDDDDDDDDDDDDDDDDDD

This, i wouldnt be suprised if the wiiu outsells it but a vitaphone re-outselling the wiiu if sony releases it

Eeeeeh higher numbers? Wii U and PS Vita sales were in the last weeks similar to each other, there is even a week where the PS Vita was higher than Wii U (here). And imagine that the Playstation Vita could be undertracked in Europe for January, which is very possible as we saw in the past. And Playstation Vita will get some hardware boosts in the next weeks, China launch, new Japan bundles, God Eater 2: Rage Burst, Sword Art Online: Lost Song, Digimon Cyber Sleuth... Wii U isn't getting anything which could boost sales in the next weeks. 

Whenever the Vita gets discontinued at retail, just after summertime