I thought of an interesting experiment.
Washington state has 49 Legislative Districts, which each elect one Senator and two Representatives on the same map. It has been pointed out before that this essentially makes each Rep. a "min-senator" and often concentrates political influence as Senators and Representatives often hail from the same part of each district.
There is no requirement that house districts and senate districts be coterminous, or that representatives be elected by position (A and B). There is a requirement that they nest.
Back before OMOV was rigidly enforced, there would a variable number of representatives per senate district, and they were not elected by position. In the 50s and early 60s, representative districts would be moved into the Seattle area, as a way to fend off a popular insurrection. So in more rural areas, there would be one senator and one representative, while in the Seattle area there might be three senators and one representative.
After the OMOV rulings were applied to Washington, there were several instances of separate A and B house districts, particularly in more rural areas. This may have been to preserve existing districts, since while the area became part of larger senate district, its representative district might have remained the same.
IIRC, the last of these were in the 1990s. There was one senate district that went down the Columbia to the Pacific Coast, and one representative district was on the coast, and the other in the Longview area.
A particular problem with the current system is the stagger of senate elections, since if a district is drastically altered, it may cause some areas to have no senator for two years, and other areas to have two senators. This is somewhat mitigated in Washington since most districts in the eastern part of the state elect senators in off years, while in the west area they are mostly in the presidential/gubernatorial year. With higher turnout in these elections, there may be reinforcement of the partisan divide. Since Democratic turnout is higher in the presidential-gubernatorial years, swing districts may be pushed to lean Democratic, and Democratic success may lead to ambitious local politicians to run as Democrats for the legislature.
In the off years, Democrats tend not to run in strongly Republican districts. There are no coattails, and no money to run a campaign.
When a representative proposed a bill that would have split the representative districts, he got a decidedly cold reception. A particular concern was that it would probably have paired many incumbents. When he suggested that this could be worked out in most cases (for you to do that, you would have to know where the representatives lived, and probably draw odd fingers to separate the two).
Those opposed to the idea mentioned the case of one representative who could look down into their fellow representative's back yard. Since it was a he and a she involved, it sounded kind of creepy.
