funny.. melanoidin malt was what prompted me to post a thread about starting a thread for various specialty grains so people can look up whaqt properties they have.
Most sources I have seen (including Baron von BeeGee) claim that melanoidin malt brings an intense maltiness to a beer. (Though, I have seen once source that says it is tangy in taste!)
I'm leaning towards it being malty since that description wins 10 to 1.
Belgian Aromatic malt is supposed to malty in aroma (but I don't know about it's taste.)
I've never used either of these grains before.
I'll sit back and let someone else who has used melanoidin speak up, but (to my amatuer brain) I would think that you could use aromatic as a subsstitute, maybe with some crystal if the aromatic imparts ONLY aroma.