Powernab (www.powernab.com) is a solar monitoring company. They install very small servers at commercial and residential sites. They have a central internet based server that archives everyones data and acts as the customer front end.
Residential introduces many problems. The central server can not address the residential unit. ISPs block unusual traffic on unusual ports. A mass market commercial product undergoes constant revision.
oBIX is being used to address all of these problems. Data is published to the central server from each site. The sites open a web address to port 80 on the server. XML documents are transferred over HTTP. To the ISP, it looks like a browser! Currently, trend records are on their 3rd revision (schema). However, the oBIX encoding layer has not had a single update since the first release.
Contact me if you want more information. My company provided the technical implementation.