Thought about Excel?
Not the g-code solution you are looking for - but should do tapered cores.
A fellow in Johor Baru, Malaysia wrote some free software that plugs into Excel 2003. Its VB based as I recall.
A search of the cnczone outta turn it up if you're interested. He also has some 6 axis source code.
Cheers - Jim
Experience is the BEST Teacher. Is that why it usually arrives in a shower of sparks, flash of light, loud bang, a cloud of smoke, AND -- a BILL to pay? You usually get it -- just after you need it.