Who's the enforcing party of this so-called ban? Are we talking slaps on the peepee here, or major jailtime for owning a piece of ivory? There is so much ivory out there right now, and they discover more and more caches of it each day. Seems to me, pestering artists who use the medium should be the least of their worries.
There isn't one spot on the planet that doesn't have ivory, so, out of deliberation... do you have enough ivory to worry about? If you craft some of it into knife handles, will the purchasers of said knife handles care? Who's going to know? Are there undercover ivory-police lurking in the shadows at knife shows waiting to pounce on unsuspecting knifemakers?
I say just use it. If anyone asks tell them your great grandfather willed it to you or something. =)
Hey just my ideas. I may be controversial, but I definitely do not mean to be offending. Peace bro, and definitely use that ivory!
Jeff