Just wanted to take a quick moment to let everyone know that Ferguson's bloodwork came back just fine. In fact, the fact that his urine is so dark all the time with the amount that he drinks (while not having a UTI) is actually the product of extremely high functioning kidneys. They process the water quickly, and efficiently. As result, the vet suggested we pick up water at about 7pm each night, only letting him have no more than 1/4 or so before bed to keep him from leaking or needing to go out in the night. So far, so good. We've been accident free, and so long as we don't do a lot of physical activity, his water consumption shouldn't change (though he did indicate his consumption was quite high, and that this might be exacerbated by the altitude and his increased energy level, since we've been visiting parks a lot more lately).
So, almost $300 later, Ferguson is completely fine. It's apparently normal for him to have dark urine and pee and drink a lot. Something to do with him being a more active greyhound than normal and his body making him feel like he needs more water to compensate with the high altitude here. Go figure.
Honestly, it doesn't much matter to me. In addition to getting compliments about his teeth, it sounds like we'll have Ferguson for many more years to come, at the rate he's going ^^.