A couple of mods have a UniTec-esque shoplist file that includes the pricing and naming of each gun exclusively. You can make your own for each faction manually, by stating a new copy of each device, like so:
Code:
AddDevice = HDFirearm
[tab] CopyOf = Gun
[tab] PresetName = Gun
[tab] Goldvalue = [value]
This should overwrite the price of the existing weapon, allowing you to set it for numerous devices in a single file. Make sure the shoplist is loaded after the devices, though.
(May have to change original device's buyable to 0, else it might create copies, though it shouldn't...)