I would definitely pay good money (like, $200) for a killer native GUI that administered both Mongo and Redis.
I'm admittedly not too tuned-in with the Mongo/Redis/Couch communities, but I do hear from a lot of folks using my native GUI http client tool to interact with their web APIs. I kind of assumed that most users of them were fairly happy to use low level/command-line tooling - is there a big unmet demand for native GUI tools for things like Mongo, Redis, etc?