Mark Wright and Ben Taylor did enormous amounts of work on porting KDE4 to Solaris 10. About half of the known universe had to be rebuilt, but the result was definitely worth it. Yesterday Mark sent a screenshot of his KDE 4.4.1 session to the mailing list.
As you can see, Amarok2 is there as well - we weren't building it for some time due to the unresolved dependency on MySQL embedded, but fortunately Mark found a workaround.
As of now there are no binary packages available, Ben will probably publish them at some point, although he might need more +1s to motivate him.