Any thoughts on a timeframe? This is the only thing holding me back from using Prometheus in any sort of serious way.
If this is holding you back from seriously Prometheus, then Prometheus is possibly not the right tool for you. Prometheus is about the here and now.
If that's not what prometheus is for, you should seriously consider adding a more-explicit mention of it in the documentation. Going through the docs, I'm finding nothing plainly obvious mentioning that about prometheus. At least put it in the FAQ, ffs.
What needs to be code-wise to get it going sooner?