Man,
Thats about the scale of work I do currently. That's what makes a U900 seem such a good fit. All in the city and suburbs. All within about a 50 mile radius.
I am still a one man outfit, and if the smaller diameter brush isn't composted on site, or gone to an eroding hillside, or river bank (palmater method), then I bundle it 2'x4' for the weekly city yard debris collection. I know this ahead of the project of course and plan accordingly, so as to time it with the collection day, usually on a Thursday in and around my main locality.
Larger diameter material is processed for fire wood fuel, and left in a pile on site, usually by the road for the lucky locals taking, with the owners approval, (or they keep it themselves, first of course.) For larger scale projects that generate more bulk of debris, then I have a list of eager customers and friends that will drive to the site and collect it, usually with my assistance in loading.
I have the Unimog to handle the chipping of these smaller debris as its much less than making these tidy bundles. I hope to just use a container to chip into off the front, thats why I have this extension off the front lift. I wouldn't produce enough to fill the back of a tipper bin, not the space with the lift. So, it may be suitable, time will tell I guess.
Up until now it has been a zen practice. No impact to the site whatsoever, all climbing, usually my handsaws or extension saws, with little use of the chainsaws, to reduce potential noise pollution, and I love when the customer comes out and doesn't even know I was there... Even when I'm there!! up in the tree or on the ground, etc..
I wish you well in going smaller. The majority of the works here are this scale, and the Unimog is really the obvious choice. It can be here, in this envirionment, what it was meant to be... a tiny implement carrier.. a swiss army knife that doesn't ride in my pocket, but i ride in it, along with my gear.
I can even get into some of our managed urban forests and parks with such a tiny footprint and help manage our invasive Honey suckle, trail maintenance, and hazard tree mitigation.
I don't take large dynamic projects that require more men, equipment, unless the tree can be felled, or pieced out with less rigging. Otherwise, I just don't take unnecessary risks.
ACUF