STEEL TEC - this was a competitor to Mechano back in 1995 and was pretty awesome.
I never got around to finishing it, but if you would like to, be my guest :)
All pieces are mostly there - there could be one or two pieces missing (after all, this is more than 20 years old), but is great for kids to start learning how to build.
Even if you don't build it, it is still a great way for kids to build and explore.
Comes with tool kit (to store pieces), motorised tools and other bits and pieces.