Thank you all for the input. My concern with a long bit was keeping it vertical while drilling all the way through the piece. I think my first try will be a bedside or desk lamp that is only about 12" high. I am getting a larger lathe, and I don't think my midi can handle a very big, heavy piece of wood. I'll save the bigger lamps for later with the bigger lathe.
The tailstock auger looks good. I'm just not sure I can invest $70 in the necessary tools to use it right now. I may try a long bit since I will only need to go 12" or so. If I reverse the stock in the lathe and drill from both ends, I can make do with my jacobs chuck and an 8" or so bit. I think I have one I used to use for cabling coax computer networks.
I've used forstner bits in the tailstock, but have never tried a spade bit. How do they work in a jacobs chuck in the tail stock. Mine have pretty long shanks and I think it would easily go 6" from each end. Or would I be better to stick with a twist bit?
I understand your predicament and you may get away with the longer bits you already have.
Drilling with twist or spade bits will very depending on the wood, the very first thing that makes the drill go off-center is wood with hard grain rings among the whole wood texture, the bits (either and all bits) will be pushed from the hard surface into the soft surface of the wood (resistance), the longer the hole the worse it will get...!
For a small lathe, I would be using a sharp twist type drill, as the spade bits require a lot more torque to work and the last thing you want drilling with a spade bit is to get the bit stuck or start grabbing more than what the motor can turn, making the bit "jar" inside pushing it off-center...!
Hope that this helps...!
Cheers
George