Grinspoon wrote Venus Revealed, a 1998 book sizing up the scientific understanding of Venus prior to European space mission that went there several years ago. (I'm not aware of a similar book today that incorporates the newest findings, and the European space agencies are doing their usual terrible job of releasing scientific information, so it might be a while to get a good new book.) At the end of the book, Grinspoon speculates that life might have survived the boiling off of venusian oceans and live today in the higher parts of the cloud deck.
I got a chance to ask him whether he still thinks it's possible and he said yes as an outside chance, although it would require atmospheric probes to figure it out. So neither the current European mission nor the upcoming Japanese one will answer the question, and we'll have to wait for a more spectacular mission.