Neil built this great modified PV Vibraphone. He has modified the frame to be a little more "permanent". Nicely done! Also note the lower strut positioned a little further back which improves the pull direction of the pedal. The downside of this is your leg needs to reach a little further under the instrument - but that's always a point of personal preference.
This is my finished Vibraphone.
It's getting a great reaction when I've taken it out. When I say i've built it people laugh cause they think I'm joking.
There's a youtube vid here of me in action with it (and the homemade mallets from your instructions) if you want to include links to them, or just have a look yourself.