The popular PEAR Services_Ebay is not unified schema compliant. Unfortunately, the author of this package is currently unable to update it. If you are interested in migrating this code to our unified schema, please post a list on the "dev" mailing list to help coordinate our community efforts.
Well, when I saw the above I just decided to bring this popular package back to the production. After submitting some patches, Arnaud and Pierre (resp. QA and PEAR Group) decided to give me the lead and removed the "not maintained" state, so I'm its new lead

The blinking point in this package is, how it is written. An awesome piece-of code by Stephan Schmidt. (nothing weird, really shining)
eBay's legacy XML API was less nested and in result setters had a great role in this package, but now high-deep elements has made the role of setters colorless and when I (and PEAR) care a lot about the BC, I've forced to override in some Calls.
eBay has done the migration process easy with providing complete manuals for developers, and that makes the migration less harmful.
Nearly everything has changed in the new API, taken from authentification to the events tracker. Although struggling with it was (is) a real pain but it's my first deep experience with enterprise web-services, funny moments.

Another thing that I'm wondering about is, to write a new mozilla extension for browsing eBay. Thanks to XUL for providing tools for a great interface, XPCom for letting me do cross-domain JavaScript requests and finally E4X (so the extension would be a FF 1.5+ one).
I'm not eager to use eBay's SOAP web-service and then using built-in SOAP support, I want to use my experiences with XML API but this time in a completely different environment.
P.S: patches or feedbacks about PEAR Services_Ebay are welcome.
If I finished my current projects that are eating up most of my spare time, I hop on board again, if that's fine with you.
Stephan
I am super excited to see some kick ass XUL eBay code, so if you run into any issues, either on the eBay or PHP side, let me know and I can lend a hand. I may even be able to share some quite useful eBay Web services XPCom code with you. Please drop me a line when you get to that stage.
PS: Stephan -- Thanks for all your great work. Hopefully, you'll have a chance to find some time to hack on this again in the future.