Diablito -
If you haven't already seen it, take a look at Frank's video - http://www.tackleunderground.com/community/index.php?/topic/22143-open-pour-video-vein-pouring/
You'll notice that he keeps his heated plastic in Pyrex cups on an electric skillet. You can get one of these at most stores that carry small appliances. They're made by Presto, GE, Rival, etc in a variety of sizes from 6"x6" and up. Prices will vary as well starting about $20. The key is to get one that will accomodate the number and size of cups you will normally want to keep warmed. Remember that you're paying for the electricity to heat the element in the skillet, so if you get a 12"x18" and only keep one 8 ounce cup in it, you're wasting an awful lot of heat and the electricity used to produce it... Then again, if you're only pouring once a month or less, it may not matter to you.
Although I've never used one, I'm inclined to believe the hot plate method (although I know some use them) would require much more of a learning curve to maintain the proper heat adjustment. Most of these units are controlled by a knob with the "1 / 2 / 3", or "LO / MED / HI" guage as opposed to the skillet which usually has a dial incremented in degrees.
Your choice will be determined by whatever you find comfortable.
Rick
SE CT