Well, mining is self-regulating. The halving is going to hurt a lot, but it's not like bitcoin's going to disappear. What becomes unprofitable to run will no longer be run, coin prices will go up, fees will go up, and the system will keep on running. If anything has a chance to be profitable, it'll be the most efficient chip available at the time. That's dependent a lot on initial cost, but the market is adjustable as well - if BitFury can't sell enough of them at whatever price, they'll either use 'em themselves or lower the price. There are way too many variables to make any sort of accurate prediction, but the fact that pretty soon 99% of the world won't be able to turn a buck with 0.3J/GH gear helps the assumed viability of 0.1J/GH gear.
This is strictly assuming that difficulty remains flat. My prediction would be price is not going to be drastically increased after the halving, as anyone taking it into consideration has already and people have already speculated at it from a trading point of view. However, majority of mining operations will maintain course up until the moment the reward is cut in half before un-plugging, which will lead to some drastic reductions in difficulty. It is very self-evident, but if difficulty was to drop by 50% at the halving (this is just for comparison, not an actual prediction), effective mining revenue would be the exact same as the block before. I.E. if 99% of the world un-plugged their 0.3J/GH and higher gear at the halving as you say, then a fair chunk of them would just plug them back in after the next difficulty drop(s). Realistically, I would expect to see a 20-30% negative difficulty adjustment in the periods following the halving.