If you have more money than sense or you really need the best, ZoBo make extensions for their range of hole drills. They also have drills ranging up to 150mm diameter!
Dom said why.....
I am doing a set of pepper and salt grinders and have to drill from both sides.
If they work out ok, I will make some of the long ones, now this is why I need longer drills.
Don't know what I would do if I made a set of lamps.
Thanks for all the help on the forstner bits.