Check out my home made rims, 3Kw element in 304 ss 2"pipe fittings. I'm waiting for the thermowell and temp sensor to turn up in the mail then I can hook it up for a test run.
$18.95 for the element from eBay, $137 for the stainless pipe and fittings. I get a pump second hand of a met for $100 and I have an old PID controller and SSR to run it.
Next step is to hook up the electrics in a project box and plum all the wet lines, I'm running a 3 tier brew tree so I'm not sure where I'll put everything. I'll post pics as it develops.
Just out of interest I saw similar looking heating devises on eBay for inline biodiesel treatment could be Worth checking out for the none handy or electrically challenged.