Again, thanks for the nice comments.
I have "play" in mind too, and here is an early look at the crane running a couple laps around the back yard to see how it behaves off road. Note that it's set up for transport, no counterweights or boom, beyond the base boom.
The suspensions are equalized to take up some uneven ground, but it's not intended to be a rough terrain crane. If it gets in to too soft of ground, it will bury in and spin the drivers (all rears are driven, fronts just steer)
I call this a 1/24 model, but it actually may be a bit large as that goes. It could more easily pass as about 1/20 to 1/22 or so, but I want it to fit in with all my 1/24-1/25 models, so I'm making the cabs and other details to match that. There may well be 1/1 cranes out there this size, I just haven't seen them. Link Belt and P&H have some that actually come close in some respects, ang Grove has some that come close in other respects. I'm combining several basic designs to freelance a passably realistic model, even if not specific prototype.
Since it is freelanced, I want to come up with my own manufacturer name. CONCORD is one that I am gravititating toward. Say, CONCORD LT6-4000
L= lattice boom, T= truck type carrier, 6=number of axles. 4000; number of tons (400), plus a zero, as so many crane companies do this! What do you think?
A side note. The basic crane, as this scales out could reasonably be able to lift 400 tons or even more at maximum, but has to be set up properly to do so with a short range, heavy duty boom, and appropriate rigging. I'm building high range boom setup, so it won't be attempting to lift the base unit's full capacity. Maybe down the road, I can build the additional equipment for heavy lifting, that remains to be seen...
Heres a mock up using a Payhauler front end just to look at proportions. Not what I'm going to use