Tracking NetBSD-current without burning bridges on release/stable version?

["Thomas Mueller" <mueller6724%bellsouth.net@localhost>]

How can one who already has a stable/release version of NetBSD installed track 
NetBSD-current without destroying the stable/release installation?

Using a separate disk, this would be a trivial question, but my question is if 
it is possible to do this on a single hard disk.

NetBSD disklabel is one for the entire disk as opposed to the NetBSD slice, and 
I believe (installboot) bootxx image has to be on partition a?

Two items of interest in NetBSD 6.0-current are improved ext2fs access, and 
genfb replacing possibly buggy (as in PR 41214) vesafb.

Tom