Don't forget the BCM versions of the 11xx and 12xx IP sets will work on the IP Office7.
I know many former Nortel now Avaya BCM experts miss the system quite a bit. I would sure love to get my hands on an IP office 7 test in my lab, but again this is all a hobby for me, so the cost isn't justified. I actually like the way 2 1140E sets I have running on SIP operate better than the way the 1140E operates on the Unistim BCM.
Now that Nortel is gone, My Alma Big Ten University in Indiana is still sticking with their CS2100 and continually upgrading, although they are having quite a few problems with Call Pilot. It was originally installed in 1997 as a SL-100, but is more up to date than ever now as a CS2100 Softswitch.
I miss Nortel Blue though....I hate seeing people recommend Shoretel and Mitel...their actual telephone sets lack the design, engineering and ruggedness of the former Nortel sets....it's almost that they all copied the Nortel sets during their design process. They may operate as great systems, but their installed base is small, their features aren't as easy and universal to use, that's why most people who have abandoned Nortel/Avaya all together have upgraded to Cisco. Cisco will let you set up feature keys and DN numbers almost identical to the BCM or CS1000/CS2100.
Anyways who are we kidding here? Unistim is dead, SCCP will probably follow. Soon everything will be SIP and all IP phones will operate identically, as the Avaya 9630, Cisco 7970 and Nortel 11xx sets I have running on SIP currently do in my lab. The only difference is the body of the phone, but since they are SIP, but the basically SIP functions operate identically on each different set.