I've actually long wished for a long-term floating atmospheric probe around that altitude in Venus's atmosphere; I think it could be one of the most favorable places in the solar system to look for extraterrestrial (microbial) life, seeing as there's lots of all the elements (except phosphate) we know are needed for life readily available, lots of solar energy flux, and a possible-but-unknown early geological history of the planet that could have had an earthly atmosphere and oceans right after the sun formed.
I was wondering what people thought of this paper by Geoffrey Landis on colonising Venus. In it he suggests that cloud-top Venus is one of the most benign environments in the Solar System. Temperature and gravity are similar to Earth, there's some radiation shielding and useful resources, and aerostats filled only with breathable air would float at that height. I'm no expert so can't speak to how accurate it is, but it's certainly very thought-provoking for such a short paper.