With some newer VCF files, particularly those that have come from structural variant callers, the rownames of the resulting `VCF` objects (when the ID column is missing) can become problematic or excessively large. To give a concrete example, we have VCFs with insertions of dozens or hundreds of bases that lead to very long rownames. While human-readable rownames are useful in some cases, would it be possible to maintain uniqueness while enforcing some further constraints on the constructed rownames to keep them manageably short and printable?   

Yes, I can imagine that's the case. The pasting of CHROM:POS_REF/ALT was a reasonable solution when ALT was just a few bases. I'm open to other suggestions of how to handle this - what information would you like to see as the row names?

We do have the option to turn off rownames with readVcf(..., row.names=FALSE).

Val