So I created a couple teas last night with coffee, and chocolate malts.
I tasted the teas separately, and mixed with the beer... (had an Octoberfest in the fridge)
Tasting on its own... there was plenty of roasted flavor, however, the flavor was sweeter than I expected. Additionally, when mixed with the beer, I noticed not only increased roasty, but a lot more perception of sweetness on the overall beer than before the steeped additions. The roasty quality was nice, but the sweetness increase was not expected.
Based on the this mini-experiment, I think I would stick with dmtaylor's recommendation of making a mini beer. After reading his suggestion, I figure I can steep some grains and add some extract to something as small as a 2L starter flask, let it ferment out, and I will have something to blend with...without a lot of effort.