Index VCF file for rapid access by rsID? With tabix one can index a VCF file for rapid variant retrieval based on genomic position. I'm wondering if there are any tools that will index a VCF file to allow rapid retrieval using rsIDs and/or other metadata? I'm aware of awk/grep/vcftools one-liners for this purpose, but I'd like to avoid scanning a huge VCF each time I need to retrieve the coordinates of a new batch of rsIDs.
I am not aware of any widespread index formats for query-by-QNAME for BAM or query-by-ID for VCF. I thought there were historical samtools{-devel,-help} threads to the effect of “in principle one could index a named-sorted BAM file, but there's insufficient demand so no-one's ever implemented it”, but I can't find any just now.

Moreover note that VCF files are by definition sorted by genomic position, so such an index would just be a hash table of rsID to file offset or genomic position.

If you are using dbSNP, probably you have a dbSNP database or API that you can use to query by rsID and get genomic position back. So you can retrieve your VCF contents by rsID in two stages: do that dbSNP query, and use its results to find the variants in your VCF file by position.