No replies in 5 years... Guess OP gave up and went away.
I found this post and since I now have the same need, thought I'd bump it up. I built a play kitchen for my granddaughter a while back which she really loves (plans were posted here), now her mom is asking for a sturdy doll highchair. If anyone here has built one and can share the plans, that might save me some time/effort.
Edit: Probably should mention that I do not have a lathe (maybe Santa will bring one), so that will limit design options.