Some guns I recently took pictures of (for sale):
Christensen Arms 1911 G5 TI
Christensen Arms CAR-15 Carbon Fiber ACOG 4x32 with RMR
Ruger RPR 308, Vortex Razor HD Gen 2
American Tactical AR Pistol, Glock Magwell, Sig Romeo 3
Yep, getting fuel delivered is nice, but you need to be burning the gallons to make it worth it. 500 gallons is as small as is common for a job site tank here... smaller than that and it'd be cheaper to buy at the pump (depending).
Containment can be as simple as a dual wall tank.
GPI is a common 12v transfer pump brand. A deep cycle battery and a solar panel can handle your pumping.
Not the best pictures, but that's a 500 gallon dual wall tank with a GPI pump, battery, and solar panel.
I've looked at them for a few years. They're too small to have any practical application worth ownership for the vast majority of tree services.
The outrigger span is huge, 60' hook height has a 770lb limit from the edge of the outrigger to 10' outside the outrigger.