Random thoughts...

For my desk, I made hardwood T-moulding that glued into slots on the
edges of everything. I did NOT want it to peel off in the future.
http://www.delorie.com/wood/desk/photos/img_1725.html

I don't know how bendable such T-moulding would be, though.

Next thought would be a bent lamination (glue-up, not steamed), so that
there's (1) no "spring" to pop it off, and (2) enough thickness to use
biscuits to hold it in place. Glue two 1/8" strips together in a curve,
to make one 1/4" curved trim piece that's pre-bent.

(if you do this, perhaps using the T-moulding idea for the two flat
parts of trim, and a miter joint, would "capture" the bent part of the
trim between the two flat trim bits)

Lastly, consider hardwood instead of plywood, or baltic birch plywood,
so that a bare edge doesn't look horrible ;-) (it's an excuse to buy a
jointer/planer if you don't have one, because you need "very flat wood"