Are they any companies out there that specialize in only installing temporary pole for electrician to install their temporary service for new construction site? Is there a term for these companies?
My Poco book lists a 6"X6" pole (braced) as acceptable, so I'm guessing the problem isn't the pole, but the HOLE? If that's the case try a landscaper, or fence builder, or whoever does your trenching.
Posthole Digger Inc. Unless you need a large pole over 25' you can set them by hand.
'We do 'temp' poles (2 or 3 2X6's) 20' (3-4' in hole) which is acceptable by our two POCO's. The hole is the hard part, but a two man post hole digger (rented) helps.
We use a pole contractor to set 'normal' wood poles. Lamplighter Electric in Morris County, as that's his "thing" with the digger derrick truck. We do light poles up to 40' with our bucket truck; taller ones use a rental crane.
Here in CA we have companies that specialize in temp power for construction sites and other temp wiring. Also some companies do complete construction rentals including temp poles, porta potties, offices and fencing. Try looking under construction rentals in the phonebook.