So, let me elaborate a bit on why I chose to propose a polar bear as a fitting mascot:
=== Five Reasons For Tristian ===
1. A white (polar) bear fits nicely with the predominantly cold blue colours of Trinity (which we mostly inherited from KDE 3.x);
2. A friendly-looking mascot with a simplistic/comic style (not abnormal flatness or geometrical abstraction which dominate contemporary Plasma et al.) looks welcome and thus effective for newcomers;
3. A bear is quite anthropomorhic and thus we can come up with more interesting designs with the bear doing something like a human would;
4. A polar bear can be both qt and strong (pun intended ;-);
5. Tristian's name reminds one of the project's name (Trinity Desktop).
Also, I can't think of another project using this animal as their mascot, so, as an extra, no legal issues.
-- Philippe