Yes, Seam adds to JSF and provides very good support for RESTful urls (i.e. bookmarkable). Take a look at it's support for page parameters" and s:link. The blog example shows this off too.
I know the s:link and s:button controls append params to the URL using page params, but is there any way to do it for the h:commandButton control, or the ajaxy submits from Richfaces? Bearing in mind the s:link/button controls don't post the forms so they are useless for data entry submitters.
The docs only really mention page parameters from the perspective of a non-interactive page (i.e. bookmarkable search results), but I imagine most people want them on interactive pages. Even if a page is read only with multiple tabs, it seems the tab click events kill the param in the URL.
I thought (and I could be wrong) that this problem could be worked around by switching from using @RequestParameter to using the id getters and setters on the EntityHome object for example and then the param was always in the URL?
commandButton submits the form using POST. Therefore no. This is something that needs addressing at the JSF spec level.