Our friends at the Santa Barbara HackerSpace are developing the tiniest ever 1.6 oz APRS Weather Data board for weather balloon flights and private weather stations. Their little device is called the Tracksoar and it contains a GPS receiver, a 2m transmitter, weather sensors, and an Arduino compatible Atmega 328P microprocessor.
They have launched a KickStarter campaign and are looking for backers. The campaign closes November 8, 2015.
For more information visit the project website at: http://tracksoar.com
The KickStarter campaign can be found here: https://www.kickstarter.com/projects/1250163085/tracksoar-aprs
Disclaimer: KickStarter campaigns involve risk. If participation in this project interests you and you have never backed a crowd-funded project before, please read this to ensure you understand the risks involved.