Removable bars - z-joint?

[PTAddict]

I'm in the planning phase of putting a 6-point (or possibly 8-point) bar into my '69 project. I would like to have removable door and harness bars, and I'm intrigued by the potential of this kind of joint:

http://img214.imageshack.us/my.php?image=m589dg.jpg

versus the usual clevis/pin double shear arrangement.

This type of joint will clearly act as a solid joint under any direction of loading, unlike the clevis/pin. On the other hand, it loads the bolts in single shear, generally considered a no-no, although without some more advanced calculations it's hard to know whether the bolted joint is stronger or weaker than the surrounding tube.

I've read all of the "mandatory posts" in this section, so I know you guys can tell me exactly what's wrong with this idea Please, fire away.

BTW, reason for roll bar install is several HPDE/track days per year. I know removable doesn't pass strict NHRA tech, but the strip is not my thing anyway ...

Oh, and does anyone know where to buy these off the shelf?