I got RealD glasses and tried it with my dual projector setup.
I do get the colour absorption you have on the pictures, however if I put the glasses at 45° angle (matching the position of my current linear filters at 45/135°). The colour goes back to neutral.
Two things to notice then :
-The quarter wave retarder in the circular polariser does not seem to reduce any brightness (at least to the naked eye), the circular polariser mounted backwards acts exactly like a simple linear polariser
-The circular polarised light is still affected by the initial polarisation angle differences that come out of the 3-LCD projector, the only thing that happens is that the colour polarisation angles switches from green/purple to blue/yellow : adding a circular filter before the linear polariser does not fix the small colour shifts in the corners of the image that I have.
3-LCD projectors do work with polarisers but have strict polarisation angles placement : the filters must be placed at the half angle between the primary colours in order to provide a colour neutral picture and there is a slight colour unbalance in the corners of the picture. The results are far from being bad, but it won't be the "ultimate" 3D projection system, only a very close contender if you don't have the money to spend on a higher end DLP or LCoS projector.