Realize that the heater element handles 1200 watts because it is cooled with a forced flow of air. If you rely on natural convection or elect to enclose the material the amount of heat you can dissapate will be profoundly affected. Note also that if the temperature of the material changes a great deal then the resistance of the material will change significantly. None of this means that you can't use the material as you would like - actually it's a good thought. Experimenting will reveal what you can do with it.
I was lucky enough to find a spool of ni-chrome wire, 28 ga or so, maybe 1000 ft, for $1 at a flea market. Apparently used at some point in applicance repair or for making resistors.
Don't overlook plain old copper wire - or possibly iron (such as a farmer would use in a fence). I recently built a meter shunt so I could get a 5 amp range out of a 500 ma meter. I initially imagined this 100 ft coil but after doing the math I only needed 10 inches. At 5 amps the wire was warm but not hot. You might find that the longer lengths needed, as compared to high resistance wire, allow for better heat dissapation.