That's an interesting idea but iOS games are massively popular because a lot of people already own iOS (or Android) devices--these potential buyers would look at this hypothetical Vita + iOS ports bundle and realize that they already own or could own those games on their phone or tablet for a modest amount of cash. No sale.
Indie games on the other hand are popular among hardcore gamers, which is basically the only market the Vita has left. Casuals are not going to flock to the Vita ever, even if such an iOS port bundle existed. For this desirable market, the second option after a smartphone is another multi-use device like an iPod touch or a tablet. Never a Vita.
I'm not talking about Puzzle & Dragons or some other brand that has no value outside of the iOS avenue. The mainstream market bought a bunch of Assassin's Creed, and Call of Duty Vita bundles last year even though the games themselves weren't exactly something special. Conversely, those indie games have been selling sub 20,000 Vitas/month in the US.