-current changes often enough, it is not practical to maintain binary packages for all versions. You either compile the packages you need from pkgsrc yourself, or use the latest available, perhaps from 8BETA (although I never checked if these are present). I personally run current on all my machines, physical or virtual, and I usually start from an ISO downloaded from
releng.netbsd.org, then I get pkgsrc and install sysbuild and sysupdate, then I load src.tar.gz and xsrc.tar.gz from -current, configure sysbuild and setup overnight cron job to update it nightly. The packages usually continue to work without a problem, there are a few one has to update from time to time - i.e. osabi, lsof and x11-links, but otherwise there are not many problems. While I have tried pkgin and binary packages, I've found that the flexibility in dealing with the sources and choosing the package options yourself is worth the waiting for the compilations.
HTH,
Chavdar