I think this is very unlikely to happen. Well, it may happen on the week of the price cut, or maybe two weeks, IF those weeks do not coincide with the launch of any of the big games Nintendo has for this yearv (Luigi, DK, Pokemon, AC). Vita will still be slightly more expensive than the regular 3DS even with the price cut - and the need of a memory card...
I think that possibility is better for someday around 2014, out of the launch of SSB and the next Zelda game, of course, or when the 3DS reaches its last months of the commercial cycle.
Anyway, the gap in sales sure would be smaller with the cut.