Anyone know if there's a mapping maintained anywhere that maps standard script record type ids to search record type and/or suiteanalytics table name ids (e.g. VENDORBILL maps to TRANSACTION)?

I've certainly never seen or heard of one

have you looked here? https://www.netsuite.com/help/helpcenter/en_US/srbrowser/Browser2020_1/odbc/record/account_activity.html