You can use nichrome wire, it is inside hair dryers. Just buy a cheap hair dryer, unwind the heating element (nichrome wire). For power control you can use PWM from an LM555 to drive a large transistor. Find out how many amps the transistor needs to be rated for by looking at the wattage on the hair dryer. Also, the heating element will work just fine with rectified DC which is what you are going to need for the transistor. The thermostat will be the duty cycle control on the LM555.

i got the wire off of ebay it was the biggest gauge they offered in 100'.