Ongoimg support for these technologies in Plone 4 would be very welcome.
I've steered away so far from using p.a.widgets in existing Plone 4 projects because the 1.X versions for the previous Plone versions tend to go unmaintained after the release of the next major Plone version where the new feature / technology is default instead of 'experimental'.
@seanupton Please use mockup 2.x in plone.app.widgets 1.x as I do. I use mockup 2.x in a own integration package. No problem with that - mockup 2.x changes were mostly due to bring it closer to patternslib.
Maybe it's useful (but I don't think necessary) to backport some plone.app.z3cform changes to plone.app.widgets.
I was doing this earlier, but trying to bring the 1.x branch to some stability first. I submitted a pull request with very recent 2.x build that I subsequently closed when confused about appropriateness of this. Currently, the unreleased plone.app.widgets 1.x now has a broken mockup 2.x circa early April (missing a link modal fix you made on mockup master April 5, IIRC).
There were a few other things I was experiencing with mockup 2.x in Plone 4 that were unexpected (broken form tabbing, in some cases), but I have not yet tracked down whether that was integration specific on my end.
I am happier to move plone.app.widgets 1.x branch to mockup 2.x if there is even a hint of consensus to do so. And I can invest as much effort as I need to over coming 1-2 weeks to make this work, and work well.
There were a variety of small Mockup 2 compatibility fixes, and other fit-and-finish improvements I saw necessary to build upon, especially for TinyMCE and Related Items patterns. I have also renamed next unreleased version to 1.9.1 (since this is mostly just fixes for 1.9 integration of latest mockup) -- all of this can be reviewed in the following pull request for the 1.x branch:
If you are using Plone 4 with plone.app.widgets, I strongly recommend trying these. Contained are fixes for TinyMCE in static text portlet, related items fixes, ability to use Related Items in any context-bound z3c.form context (not just add/edit), and a few other minor things.
My only current known outstanding UX issue with this integration is broken progress bar on TinyMCE uploads (this is likely only a CSS omission).