What are others doing to cover the viewfinder/eyepiece during long exposures? There is no way I am going to slide the rubber eyepiece out, find someplace to put it then slide the rubber/plastic cover that Canon attached to the camera strap onto the viewfinder.
I have been shielding the viewfinder with my hand but was wondering if anyone has any good alternative suggestions.

Not a solution, but my Nikon D700 has a switch that closes an iris over the eyepiece glass to prevent light from entering. All SLR's should have this.

Simple. Use metered manual exposure. You set the exposure while metering with your eye to the viewfinder. Once the exposure settings are locked in, you can leave the viewfinder wide open; it won't affect metering anymore. With mirror lock-up, you won't get enough light leakage to matter at the sensor.