I'd love to suggest that Aria player and Aria engine are available also with plugin format *aax.
The sad story behind this is that Gibson has killed off Cakewalk, the product will neither be sold nor developped anymore. (Please see http://www.cakewalk.com/Gibson-Announcement.)
As a user of Sibelius (8.7.2) it was a small step for me to replaye my #1 DAW Cakewalk Sonar by ProTools (12.8.2), but alas, ProTools takes only plugins with the format .aax.
I actually love the crisp and clear sound of the Garritan P.O., as well as the J.A.B.B., and I would be devastated to miss them in my further work when using a DAW.