Curve Tracers

Gentlemen,

Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're
typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
 I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted
this? I'd be interested to know what the main challenges are likely to be.

-CD