Mark and I live about 24 miles from each other, and I have known him for a few years now. He has come a long way with his ZR550, and has even been doing some track days on it. Will he eventually start racing? That is up to him.
I feel for you on this subject Mark. You can finish the project you have and get another and go a different path, but if you need to sell the ZR to fund the other, because you don't have the space for 2 bikes, that is you call. Maybe get a storage for the second bike? 615cc with lumpier cams really wakes up the 550, from my experience on the track and the street. Reliable in daily commuting? I don't see why not. You have a choice of 615 kits. Wiseco 10.25:1, or from Dynoman, his 12:1 Kit. I have had conversations with Dynoman and running our pump gas limited 91 Octane would not be a problem with the 12:1, and non-stock cams. No need to run race gas. Gary is running the 12;1 and Web Cams (#1264) in his 1984, and loves it. This is very similar to Megacycle's 478-60 Grind.
As for another bike, the ZXR1100/1200 is always calling my name. They have the look I like, and options to upgrade performance if needed.
Good luck on your search, and by the way, we still need to ride sometime.
EDIT: Here is another ZR550 Project for you
losangeles.craigslist.org/wst/mcy/d/kawa...sale/6771513322.html