A crash at some point? Most likely, yeah. The exact formula for causing a crash would most likely be to artificially inflating the price of an asset to the point where it cannot be supported.
Think Silver in the early 80's when a couple dudes tried to corner the market and eliminate the supply. Only now it's the dollar that's being artificially deflated in order to lift everything else, and the bonds which are being inflated to support low interest rates by the Fed.
If we get a crash I'd expect it to start with bonds, Cause the mother of all spikes in interest rates, leading to a parabolic dollar, and finally cause all other assets to rebalance to deflation.
If the Federal Reserve cleared out of the market with their purchasing of Treasuries, interest rates would be far lower today than where they stand at the moment. Accommodation programs have merely kept interest risk premiums elevated to put some support under other asset prices.
Interest rates have done nothing but risen from the last week of July-2012. The introduction to further accommodation commenced in a Hilsenrath piece in the first week of August-2012. Accommodation programs have not lowered rates-No-They have raised interest rates.