Mike,
I found this alternative with temperature sensing feedback that you could build. Its was developed by Don Clement (also makes the Clement focuser)
http://www.atmsite.org/contrib/Clement/dewheater/
AndrewJ also seems to have some good tips on this subject seem my new scope LX90 thread.
Other homemade ones
http://www.backyard-astro.com/equipm...dewheater.html
I like this idea of using a coper tube to hold the resistors as a dew heater. Nice comfy fit. But i would not want to have an accident so close to my corrector.
http://www.beevo.com/Dew_Heater.htm
Off the shelf solutions:
I also called up Astro-optical today and they custom make controllers for you. Depending on how many heaters you want to use. I was quoted about 150$ for this, but you can get a Thousand Oaks controller new for the similar price at myastroshop. They sell the Astrozap heater straps and the Astrozap flexi dewshields. Also the Kendrick Mark IV dew heater is in the same price bracket as the thousand oaks one.
I have read many good things about the Dew-not heaters combined with the dewbuster controller. The Dewbuster unlike the thousand oaks and Kendrick Mark IV has temperature feedback. This is about double the cost.
Then there are the Digital Kendrick line of controllers. And another on from the UK called Revelation Pro.
Regards
Fahim