Caveat: in the US you need an amateur radio (ham) license to go down this route.

I'm setting up an APRS station this winter and attaching it to my weather sensor rig. As I'm fussing with all this, I started thinking, can I make a beehive-scale APRS station? Or maybe have multiple hosts operating on QRP frequencies with a line-of-sight between the hives and the base/collection station.

Anyone else thought about using QRP or Part 15 compliant networks for getting data back to home?

Excellent thought. DStar would be another good candidate now that they handle location. I'm wondering about the unmanned transmission thing though. I know that repeaters don't need to be manned but do the actual stations?
I have an APRS unit if you want to do some testing.

KF5JSA

In the US, the APRS stations don't have to be manned if they're operating in beacon mode and following all the related rules. If you're running at 144.39 and low wattage, the signal will barely make it past your house. However, if you have APRS station in your house it can collect and propagate signals that your community might care about, like weather conditions.

Here's the APRS map for greater Pittsburgh, it's mostly WX stations: http://aprs.fi/#!lat=40.49780&lng=-79.83230

I think this is legit, but I need to check with some other hams:
KG6ZVQ-0 is my home, and -1 is my truck. I could decide that -9-15 are reserved for my beehives. I would run those at very low power (so they can run on batteries/solar), just enough mW to get a strong signal to my house, -0. That -0 host can collect/log the data and only send WX data to APRS-IS. The beehive-related data could be emailed / texted if it was urgent.

Keep us posted, I'm just getting started on a monitoring system and haven't committed to a wireless technology yet. I think this is a viable way to go if a person is set up for it. I'm more familiar with DStar and have a DVAP and repeater, so I may try that route.

I am using Moteinos with RFM69 modules to transfer data from the hive w/ hacked bathroom scale to the computer in the house. Depending on the distance this might be an option.
Work still in progress and in prototype stage. Currently I try to port the receiving side to a RasPI to avoid having to run my computer all the time.
You can find the sources here, but there is still a long way to go in terms of documentation.
https://github.com/mkoegel/BienenBoxWaage
The start of a project documentation in German is here: http://guckimker.tumblr.com/BienenBoxWaage