They make "rough terrain" type scissor lifts that construction folks use outdoors. Gas/LP engines. But, they're wider & may not be as compact as you need for working around the bins. They have larger ATV tires also that allow them to work on softer ground. But, they still have "tip" sensors that will stop it from lifting if it gets too far off level.

I vote for the "boom lift" that someone else suggested. I wouldn't like the idea of the telehandler & needing 2 people to go up. A good boom lift isn't cheap, but you'll use it for more than just bin work, I assure you. We have an 85' that we use all the time when working around the bins, and lots of other things. The boom lift makes it easy to power wash the top of things too, like big tractors, combines, etc.

Once-upon-a-time, we either used extension ladders, or took the 4020 w/the loader & put a 12' step ladder in the bucket to get someone up high enough to work on the roof. Ironically, no one was ever killed. 

Best place to buy a used boom lift is from a rental company that turns over inventory occasionally. If you buy one from them, ask them to do a state-type inspection before you pay. We have ours inspected annually just so everyone can sleep at night. If at all possible, store it inside. It will then last forever. When stored outside, the weather & sun take their toll. Finally, I would recommend to NEVER rent it out. Letting a good friend use it might be one thing, but getting money for it could be a problem if anything went wrong.