i would have to say go with LP because the cost of running electrics in a 3 shift operation would far outweigh the cost of running LP Gas trucks.
The expense of extra batteries not to mention the maintenance of these batteries, yes they would require constant maintenance and cleaning.
Also constantly running electrics keeps them hot most of the time and heat is generally bad over a long period of time for any electronics.
In most of the companies i've done work for that have large fleets of electric trucks they are constantly in the shop for a myriad of assorted electrical and hydraulic problems due to the constant heat that an electric truck generates.

Yes the hydraulic issue would probably also exist running LP trucks but i believe the LP truck stands up better in an atmosphere like this. The accounts i deal with that run LP trucks have alot better track record than the electrics do imo.

As for the fuelcell option? I wouldnt waste my time with those, the technology is way to young to make any type of viable resource with it... the cost of those is no better than regular battery power. The dealer i know that tried to push these fuelcell packs on some customers finally wound up canning the idea because they require alot of maintenance, repair costs are rediculous and the tech requires specialized training to even work on them and has to be certified due to the EPA laws.

but its ultimatly up to you which way you want to go.

happy hunting :o)