The advantage to ribbon mics is that they take some of the "edge" off that you would get if your were close mic'ing brass with something like the SM81. Since you were asking about a darker sound, this was the obvious answer.
On the other hand, using a kick drum mic might be too dark, although it's always worth a try if you have one lying around. I have used an ATM25 on trombone, but found i had to add a lot of hi EQ later.
There are a series of ribbon mics by Beyer that can be found used for around that price. They're a little noisier than the Royers, but still nice mics. Maybe someone can remind me of the model numbers... I believe M280 was one, but there are a couple of others.
The small diaphragm condensers would be very useful for room mics, or mic'ing from more of a distance, like in classical recordings. That would imply you need to first find a room with a good sound.