Man you guy's are off the hook! It will take me a while to digest all the information in this post. I can tell you now that i have power on top of the hill. VIA my well house/head, however i can't remember whats run up there but 12/2 or 14/2 seems likely. I also have a dual xeon work station sitting here with 24 gig's on non ecc memory. The station is not doing anything at the moment. I think I have 950watt power supply in it and I also have a PPOE switch sitting here as well.
Well just a few points about your power feed: 12/2 could be adequate, and 14/2 might be depending on the length of the cable and the size of the water pump, but there a few considerations.
First, are you sending 120V or 240V to the pump? Many residential water pumps run on 240V. That alone would not necessarily be a show stopper since many computer power supplies will run just fine on 240 volts, though you may need to flip a switch on the power supply to select the higher voltage, and get a 240V outlet and a compatible plug - it would be illegal to use a 120V outlet for 240V due to the risk of someone plugging in a 120V-only device. But that may not be the biggest problem. The pump is turned on and off by a pressure switch. If that switch is up at the pump you're golden, you just tap in to the power line before the switch. But if it's down at the house, and often it is put there so it doesn't freeze in the winter, then you don't have continuous power coming up that line, instead you only have it when the pump is actually operating. So that's the first thing I'd check, if you're not already sure of how it works.
Also if all you have is 240V then if you have any networking equipment up there you'll likely need to replace the "wall wart" transformer(s) with one(s) of similar output, but 240V input (unless the "wall wart" is a switching type supply rated for input voltages up to 240 or 250 volts - some are, but don't assume that, check the label). You could just get a big step-down transformer to take 240V down to 120V and then run your 120V equipment off that, but the dual conversion will be less efficient and your electric bill may be a bit higher doing it that way. Since most of the world outside the USA and Canada uses 240V as standard household voltage, it shouldn't be hard to find transformers that will work.
There is, of course, the highly illegal and potentially very unsafe option of using one leg of the 240V feed and the bare ground wire that is (hopefully) in your feed cable to get 120V. Please don't do that. For one thing it assumes the ground wire is correctly connected all the way back to your breaker box, for another if you have any GFI breakers or outlets in your home you can cause a load imbalance that will cause them to trip, possibly even if they are on different circuits. But maybe you have one of those water pumps that actually runs on 120V, in that case if it's only 14/2 I'd worry that the pump is using the full 15 Amperes (the maximum size breaker when 14/2 is used) and that any additional load would trip the breaker. With 12/2 (and especially if it's a 240V circuit) I would hope there is enough headroom there that your computer can operate without causing so much load that it trips the breaker, but you won't know until you test it.
One other consideration is that heavy duty motors such as well motors can cause serious "kickback" voltages when they shut off, so you will want some VERY good surge protection between your electronics and that power line, and I am not talking about a cheapo surge suppressor strip from Best Buy or Staples (which wouldn't work with 240V anyway). It's probably worth it to drop a couple hundred or so on excellent surge suppression if your only option is to get power from a "noisy" line that has power spikes whenever the pump shuts off. Another option would be to use a UPS that is totally isolating (the commercial power is used ONLY to charge the battery, and the equipment is constantly fed from the battery only and never directly from the commercial power) but those can get rather costly too, as I understand it. If you are really into electronics maybe you could even build a 240V or 120V battery charging circuit that charges a deep-discharge 12V battery or 24V battery, then build appropriate circuits that convert the battery voltage to whatever voltages your equipment actually needs, but I really can't see any of that being less expensive (or frustrating if you're not an electronics genius) than just running a totally new 120V circuit up from your house. And that might wind up being your best option, particularly if you plan to dig another trench for fiber cable anyway. Unlike Cat5 or Cat6, there's no problem running fiber optic cable in the same conduit or plastic pipe as an electrical cable, since it's totally non-conductive. I can certainly understand not wanting to do that, since nobody hates digging trenches more than I, but I'd also hate to see your equipment damaged by voltage spikes from your pump.