Don't post here much, but I live in a Denver suburb and have never heard of such a thing.
I'm pretty familiar with the skoolie world around here - I drive limos and party buses for a living, own my own skoolie/am shopping for a second one, and am experienced in spray foam insulation, wood stove and off-grid solar installation.
Not sayin I know everything, but I don't think such a place exits.
Then three's the space issue: the "front range" counties that make up the I-25 corridor all have exploding populations and metastatic bureaucracies. Housing is well into bubble territory again, plus the marijuana industry has bid commercial and industrial space even further off the charts.
Josh at Tiny Visions, Inc.
sells used buses when he has them, and two of his customers are paying to store and work on their bus on the lot in Sedalia. There's not much space there, and the primary use for the lot is his family's paving business. I doubt there's room for a third, and I doubt it would work at all unless you bought your bus from him. (This wouldn't be a bad idea if you're going to a dealer around here. He strikes me as FAR more honest than any competitors...)
Colorado was a great place three million people ago!