when confronted with a rather unusual instrument like this, it pays to use two different types of mics (on separate tracks) to cover the anticipated problem areas. the dobro will share some characteristics of acoustic guitar, but is likely to be much thinner in the low end, and will probably need some warming up. my approach might be to use a small capsule condenser, slightly off-axis at the upper end of the instrument and close in, and couple that with a ribbon or small capsule tube condenser also close in on the lower end of the instrument. use a blend of the two mics to get the right frequency balance. frankly, i am using that technique on all kinds of instruments lately with great success, and find i hardly ever need to use EQ to "fix" the original tracked sound, since i can accent the highs by using a little more condenser, or warm it up by blending in a little more of the ribbon mic.
