A simple way to get much of the flavor benefits of a decoction is to do a pseudo-decoction. I have an article about this technique in a recent Zymurgy. It's simple. Just do two parallel mashes, one in a biggish kitchen pot (I use an eight quart/liter pot) and the other in your usual mash tun. I like to mash 1/4 - 1/3 of the grain bill in the smaller pot, and I put it in a preheated oven to keep the temperature.
After mashing the smaller one for thirty minutes or so between 145-150F, bring it to a boil and boil for thirty minutes, being careful to stir and not scorch. Just before starting the boil, mash in your main mash, again between 145-150F.
Then carefully add the boiling smaller mash to the main mash, which should boost it up to around 158F. While you've destroyed the enzymes in the smaller mash by boiling it, most of the starches were converted, and there is enough excess enzyme activity, even when using 100% dark Munich malt, in my experience, to get complete conversion, and actually, increased efficiency over a straight mash.
I actually place my eight quart pot inside a big 21 quart pressure cooker, which does several things. It produces even more of those yummy melanoidins, it does it quickly, and it eliminates the need for stirring. As a matter of fact, I did this Monday, and the smell from 100% Vienna malt coming out of that pressure cooker was beautiful.
My favorite recipe for this method is a Dunkel with all dark Munich and a touch of Carafa II. The recipe in the Zymurgy article.