I have the Qu-ax reinforced and do allot of 360 spins 
The reinforcment will NOT be in the way.
Peter M
For the record, since I didn’t see it stated outright here, as a general rule, using conventional welding methods, dissimilar metals cannot be welded together, however many dissimilar alloys of the same base metal can be (you can weld steel to stainless steel.
That means, no combination of titanium, magnesium, steel, tungsten (why would i mention that, it’s heavy as hell)m, or aluminum, can be welded using TIG, MIG, conventional Torch Brazing, soldering, oxy-acetylene welding, or something else of the like.
Good luck. You could always go on ebay to get a suitable titanium plate to use for the top mounting bracket. As for machining, Ti ain’t too bad to machine. If you’re just drilling a few holes, you would be fine.
Ivan, it’s on the way to you now 
Cheers, thank you!
And that engineer is really good, he knows what he’s talking about. He designed and built a new concept helicopter himself and now there’s quite a bit of demand for it. I’m sure he can handle a unicycle seatpost.
I’ll bring my Thomson, the titanium pipe(thank you, Gazza) and the broken plate and see what he says.
Maybe it’s not worth it and it’s easier to reinforce the stock seatpost. But it’s heavy as hell. What’s the point of getting a super-light titanium frame if your seatpost will weigh have of the frame’s weight?