[rurban]

I automized constant rebasing. it's a couple of cronjobs for the mirrors and projects I'm maintaining over several years, and the cost is marginal. I get about one failed rebase email per month.

a big project of mine is about 2500 commits ahead. rebasing this beast is partially automated, but still I get about 2000 upstream changes through once a month. you need scripts to rebase and to rollback for a wrong choice.

it scales trivially.