Check out this link. (Amazon link at bottom of this post) It may be a fairly reasonably price option for you. I have this setup, and it's worked well for me. Not perfect, but perfectly workable. It will keep a rolling boil on about 6.5 gallons and get there fairly quickly. I think the heating element's around 1650 watts on 120 volts.
Caveat: The heating element is not failproof. Mine burned out after about a year's fairly heavy use. 14-18 sessions. I thought the whole setup was toast, but when I called the manufacturer I found that they'd ship me another heating element ( heatstick, really) for $28.00 post paid. The new unit worked great, and I'm back on track.
An additional thought: The heating element just hangs over the side of the liquid vessel. The bracket the heating element hangs on trips a switch on the back of the heating element that allows it to turn on. It seems to me that the heating element safety switch could be easily bypassed by an external wedge to close the circuit. That way the heating element could be used in any metal vessel, not just the Cajun cooker, as it's a fully enclosed and grounded unit.
So, if you already have a nice aluminum or stainless wort cooker, you could call the Cajun people and just order the $28.00 heating element and hang it on your existing pot. It's probably cheaper, and better made than most heat sticks.
BTW: I cracked open the heating element that went bad on me. The electronics for the thermostat control and the LED readout were the problem. I was easy to I.D. the key wiring and rewired the unit to bypass the thermostat and readout elements and connect the 120v and ground directly to the calrod. Works fine and will use for a backup or to heat additional water in a stainless steel pot I already have.
I've ramble on here, and may have lost the thread, am on homebrew number 2, my limit, so bare with me. If you have questions, let me know, I'd be glad to provide further details.