Umm can't say it's impossible, but really unlikely.
The sales volume is too low, even introducing a new model wouldn't change things at this point, cutting the price doesn't make sense either because the uptick in sales would be really modest and wouldn't offset the lower margin (not to mention that you can already find a Vita 2000+different digital games bundled+8GB memory card at 169$ easily) so they would just invest in something without a meaningful return.
Also the system doesn't have a long life left anyway, I doubt it will survive past 2016, so it doesn't make sense to invest in a Vita 3000 and they clearly don't any any plan to relaunch the system, actually they have pretty much decided to abandon it to focus on PS4.