I have been wanting to convert to an electric HLT for a long time. I finally decided to brew after a long time not brewing and figured since i had to clean all my stuff real good i would try to convert my HLT to electric, or mostly.
So my first try was with a water heater element and a control from an electric range(for a burner). It worked good. I also wanted to try a water heater thermostat. So i tried that and it worked awsome. The highest setting is 150. I got 10 gallons to 162 in 1.5 hours. Not real fast but i will put it on a timer so its almost ready when i wake up on brew day. It took about 10 minutes to get it to 170 on propane from 162. I may add a second element and control it with the range controller. The water thermostat will work with the other to get it to 162 and then the range controll will run 1 element to get it the rest of the way. Or i may do away with the water heater thermostat. We had a great brewday and so far i love the electric part. It was quiet and i didnt have to worry about propane burning my shop down. Although i had had a few brews when i fired up the propane and removed most of the hair from my hand!!
I am not an electrician (although i have done alot of electrical work,110 and 220)and if you decide to try this setup have an electrician help. My kettle was grounded and the cord plugged into a G.F.I. outlet.
Here are some pics. I will add a better cover later on when i get the setup dialed in.

I used a high temp silicone o-ring on the outside of the HLT so it needed no pipe tape.

On the inside is a copper fitting that threads onto the element.

For bigger pics here is a link to my website.
http://flatfenderbrewing.com/kettlebuild.html

Very nice! I've been thinking about this for awhile, but havn't had the gonads to try yet..

It took me awhile to get the nerve to slice into my perfect HLT with my plasma cutter. I did not have a hole saw the right size so i had to freehand it then smooth with a die grinder. Worked perfect though.
I think i am going to switch back to the range controls and mount them on a panel out front. I have three of them so i might do 2 in the HLT and 1 in the boil kettle.

I'm to simple to make one of those.. My wife would find me laying in my garage with a stir stick in my hand.. I may be a lot of things but an electrition, I am not..

The electric part doesn't scare me. It's the whole " $30 for some parts, or $30 for the igredients for another batch". Guess who usually wins . One day I'll do it, but not yet.