One option might be to source out two big step up/down transformers and do your own HV transmission line. Though if this is 3 phase it gets more complicated. If 3 phase is not a requirement you could do a single HV line with a centre tapped transformer at the other end to get a standard split phase service.
If this is a new installation, how about having the power company supply you with 4160 service, and you get two 4160/480 transformers, one at each building? (I'm assuming the 850 feet separation implies two buildings.)
We have 4160 distribution at our university, they have a master 4160 breaker panel, and then send the 4160 underground to each cluster of buildings. They have pad-mount transformers at each cluster, feeding whatever the building needs, either 480, 240 delta or 120/208 Wye power.
With 2 buildings, this may or may not make economic sense, but with more than 2, it really starts to be better.
Shipping 480 V 850 feet could lead to real issues with harmonic distortion and as others mentioned, severe dips when large loads are started.
Jon