I have added a USA state legislature tool. This is really self-serving on my part as I was looking for way to easily see the make up of all the state legislatures in one place to be able to use that information if we (my wife, son and I) decide that we need to leave California for redder pastures.
You can see how the tool works on the main USA page. You can drill down to individual states if you desire. The permanent link to the tool is in the upper right hand corner (on desktop sites).
This has just started, but I hope to have all 50 states up within the next few weeks and then also add other information that can be used to help better determine what states have a good possibility of remaining safely red for the foreseeable future.
Hope this helps some of you and please let me know if you have ideas that might help in this endeavor to determine what states are solidly red.