I am not sure to understand your question. Nothing forces you to dump the full Fossil tree to Venti every night. You can run snap manually every time you want, or run it only on a part of the tree.
You can also individually exclude some files from the snapshots using the DMTMP bit. If you really want to avoid archiving binaries, you could simply add a cron job which automatically apply the DMTMP bit on the binaries just before the archival snapshot. Fossil and Venti are very flexible, you can do almost everything you want. -- David du Colombier
