So I have made a bit of progress - the jar we want to depend on these days seems to be called: geoapi-nogenerics
I have made a branch for geoapi-2.1-M0 and hope to here back from simone (and ensure it represents something he can make trunk compile against)
before actually nailing this down and making a geoapi milestone release. I suspect he may want me to rollback some coverage changes they made...
Changing things over to trunk right now seems horrible ...
C:\java\geotools\trunk\module\coverage\src\org\geotools\coverage\grid\GridCoverage2D.java:[145,7] org.geotools.coverage.
grid.GridCoverage2D is not abstract and does not override abstract method evaluateInverse(org.opengis.util.Record) in or
g.opengis.coverage.Coverage
(These above compile errors have been fixed to some extent on the FM branch)
So I will stop my experiment .. and wait to hear back from those in grid coverage land? When this is sorted out we should have a nice GeoTools 2.3 milestone release for WCS 
Jody