The "two E10Ks" part is the important part there, as you need a very powerful server to support SunRay users running Solaris. At my university there was something like 200 SunRays supported by cluster of T2000s (7 nodes IIRC), it was fine for CDE, Firefox and few dtterms, completely unusable with Gnome (it took Gnome like 10 minutes to even start).

On the other hand I have heard of some success stories about using SunRays as RDP clients, which is actually supported configuration (you still need a Solaris box that manages the sunrays and translates RDP to ALP).