Jay, I have had nothing but great results doing 3D with poplar. It molds very nice, is easy to sand, and is easily available from big retail outlets for a reasonable price. Try experimenting with settings/bits, may be worth the effort.
This was done using a .25 for rough, and a tapered spiral [tapers from .25 to .9] at 16,000 rpm for finish.
Did this polar crucifix the same day, as you can see, the detail is very sharp, and this pic is right off the machine before I even did any finish sanding or clearcoat.
Rick, like you, I am attracted to unusual grain/knots/imperfections that give the piece character - So much so that I will usually cut and set up a piece with these in mind, and I specifically look out for this stuff when buying wood. Lucky for me, I guess, that I don't have any customers to worry about ! But just like there are coin collectors who love tone and [what most would consider] defects, there surely must be alot of folks who would rather buy something like this rather than a generic, plain looking cut.