Converting the wpkg scripts to appinstall doesn't seem like that difficult of a task, mostly just time consuming.
It's harder than it sounds to actually get a few useful app tests written. Plus there'll be some work writing up and fixing the bugs it uncovers.
That is why I thinking working on tying it into test.winehq.org is more worthy. I still think tying appinstall and patchwatcher together would be beneficial and allow people submitting patches to see where regressions pop up in software, and to see what new software works with each submitted patch. Perhaps a project of implementing all of this and adding wpkg scripts would be accepted?
Arjun Comar is going to propose something similar, but using Buildbot as the point of integration. - Dan