Short while after making this post I stumbled across nostr:npub1cmmswlckn82se7f2jeftl6ll4szlc6zzh8hrjyyfm9vm3t2afr7svqlr6f with nostrsync.live

Looks like it's not automated, but it is an archival tool for #nostr

nostr:nevent1qqsv0zpwjw63sejdl0jta4w7hqmxx2qkwp2hjzug4jpv5zp33fx96jspz3mhxue69uhhyetvv9ujuerpd46hxtnfdupzpnzpuqqnty8njquwsltj6pyr3xczyaqlnxdwz7vscvj8e2dy7uytqvzqqqqqqymmje65