The SP-Cycles frames are pretty inexpensive at around $350-400 delivered to the USA.  I haven't priced any other open mold hardtail frames so I can't say how they compare.  I will say that right now on Probikesupply.com you can get a DV9 for $1068.  Yeah, it still a lot more money but you get a quality frame with a lifetime warranty.  If I only needed to build up 1 bike and I liked the geometry I certainly would strongly consider paying the extra money for the Ibis.  I needed 3 hardtails and I will actually need to buy 2 more frames to migrate from size medium to large when they grow.  So it was a no brainer to go with the best/cheapest option I could find.

I wouldn't call the 177 improved at all. It's basically a non-aero version of the 168. Might be lighter but it's not an improvement in my eyes. The 268 is an evolution for sure but that weird quick release thru axle thing is a big step backwards to me. But everybody can have their own opinion. I'd still pick the 168 given the choice of all three.

I've ridden the 168, 177 and 268 now. I would agree with the earlier assessment that the 177 has considerable upgrades over the 168 in terms of stiffness and weight. The 268 is a great combination of the latter two and my favorite frame so far. The new speed release style axles took a little getting used to, but have been totally fine and often more convenient.

What direction did you take? 

Tan Tan FM639, still waiting for paint and delivery. IMO Velobuild is less of a gamble.

Price should remain important, although it is trending in the wrong direction...

In the last Nero's show, although they were a bit off on the historical timeline of Chinese frames, they presented what they call a "third wave": branded frames aiming to sell for half or less than traditional brands

Good point :-)
Looks like a good one, maybe the price could be lower, but still..numbers are good and quality as well (I have a 909 allready)