Hansgrohe makes an ideal valve for that situation, its interaktiv series. It may seem a litle pricey at first but it eliminates the need for an in wall diverter.
They have three different rough valves to choose from. One is a standard type valve for a single outlet or a diverter spout for showerhead. The second has two outlets, you turn the handle clockwise to use one outlet and counterclockwise for the other. The third has three outlets, again controlled by the handle.
The temperature is a controlled by a spindle in the handle. The rough valve is $100, the cost of the trim varies according to choice. The faceplate and handle cost about $250. The complete tub shower trim is about $450. That may seem a little pricey but it actually has a very nice "air powered" showerhead.
Personally I only purchased the faceplate and handle as I will be using a slide bar and will buy the spout seperately.
This also eliminates a lot of the inwall piping required with a diverter/transfer valve.