As [MENTION=419049]WizardOfBoz[/MENTION] suggests, I typically see thinner wall tubing used for threadless than for threaded steer tubes.

That is an idea to take the threadless and threaded steer tubes, and splice the two somewhere in the middle. It should be strong enough, although any joint would be completely hidden.

I'd encourage you to give the threadless a fair shakedown. You may come to like them.