I've had good success with the Wolf Faust IT8 targets. I profile for each emulsion that I scan, with the matching Faust target, and the colour balance is generally OK. I have not used the Epson scanner - I use a Nikon 5000ED. A lot of my slides are on the blue side, as they're taken at high altitude, so my post-processing workflow often includes a colour temperature conversion.
If you are getting a consistent colour cast, I wonder if there is a second colour profile sneaking into your workflow somewhere? Or perhaps there is some non-linearity in the Epson's colour response that's giving you a colour cast?