The best solution I can offer is to save your default model Tree, then add whatever parameters you want to sometimes see and save that model tree also.
then create a mapkey to switch the model tree display to whichever you want to display at this time.
I have 2 saved model tree's
1. standard model tree doesn't show much....just feature number, status, feature ID, Current Rep
2. dwg model tree shows shows .... drawn by, drawn date, checked by, checked date, dwg title1, dwg title2, dwg title3, commodity code
to toggle between them I have 2 mapkeys "smt" standard model tree "dmt" dwg moldel tree
simple 
My solution is actually a combination of all the above... (although I realize it is a luxury that is not feasible for everyone)
Purchase a second monitor. Set the RH monitor as your primary and LH monitor as secondary. (similar to what was suggested earlier, but better 
)
Set your configs to display the tree as a separate window. (as Don Anderson suggested)
Create a mapkey that places the model tree on the RH edge of the LH monitor.
Create other mapkeys that toggle between different trees styles as needed. (as David McClinton suggested)
After it is all set up, Creo will launch on the Primary monitor and the tree comes in on top of your design window (by default), all you need to do is hit your mapkey (F9 - for me) to pop the tree over to the LH monitor. In the end you get a large design area on the RH Monitor, and as large a tree as you want on the LH monitor. Best of both worlds. Not to mention that you can also run e-mail and your favorite music player on your LH monitor as well without interrupting your Creo design space.
Good Luck
Bernie
Bernie Gruman
Owner / Designer / Builder
