Tall bike build

Ive got two frames and know a good welder. is there any good advice for building a tall bike, whose the best person to ask?

my main concern is connecting the forks to the handle bars above the top bike. how is this done?

If I was to build one - I would possibly suggest, putting the headset and forks onto the bottom bike, then welding an old front axle to the top of the headtube. Use the old axle to bolt on the forks of the upper bike.

If I was to build one - I would possibly suggest, putting the headset and forks onto the bottom bike, then welding an old front axle** to the top of the headtube**. Use the old axle to bolt on the forks of the upper bike.

that won't work.

You'd need to find an old steel stem and put it in the bottom frame and weld the forks or the axle to that.

I would recommend doing it properly, find some 35mm mild steel tube and make a super long headtube, and extend the fork steerer and use ahead to connect it all up!

Im going to get some steel tube from work. is 35mm the correct measurement. I can get 25mm tube fairly easily. found a good welder just need to convince them that this isnt a stupid idea