Yes the SR25 is still in production. The model that the US Navy and Spec Ops in general are purchasing is the Mk11 Mod0. The Mk11 can be had but it ain't cheap at $5300 for just the rifle and $8000+ for the system.
The SR25 was in production before the modern AR10 with pre-ban varients being out there. Knights is supposed to offer them for sale again in the near future though the wait is going to be a year + long. So far Knights has been swamped with Gov't contracts and isn't offering much of anything lately. If you want one your best bet is to look for a nice used one preferably of recent manufacture.
I just got an SR25 Lightweight Match that I sold my G.A. Precision AR10 for. I'll be sending this off to G.A. Precision to upgrade it to Mk11 Mod0 specs. Generally speaking, if you take the accuracy of a SR25 Match (24" bbl) and an AR10T, they are both pretty comparable in accuracy. Of course, the SR25 is about $1500 more than an AR10T. Is the SR25 worth that much more than an AR10T? No, probably not but the pride in owning something that not many people have or you don't see everyday is worth it to me. In my case, I also collect military precision rifles. A Mk11 Mod0 (or clone) will fit better in my collection than an AR10 and will look nice with my Mk12 Mod0, Mk12 Mod1 and USMC DMR.
I'll try and get pics up for you in the next couple of days before I send it off. For more info you can check out www.SR25.com and www.knightarmco.com.