Supported cards: jcop31bio cards that include the "bluez" applet in their rom mask.
This includes the sample cards that you can sometimes (but not presently) buy from IBM. We do not know if any of the manufacturers/resellers of non-application-specific 'jcop30' cards provide this rom (or even if any of the providers will provide cards that are still in the OP_READY state).
jcop21id cards could work, they are fips compliant and thus require secure messaging, and the opensc code has secure messaging, but noone gave us feedback this far whether or not it works, so we have assume that it does not :(
IBM recently released the jcop40/41. We do not know if this card provides the applet. There do not yet seem to be any 3rd party manufacturer/resellers.
Note that pkcs15-init cannot initialize or erase jcop cards. There are no free tools to do that in OpenSC.