Blending between arbitrary numbers of textures on the same material

How would you blend linearly forwards as well as backwards between x number of textures on the same material?

I've found a shader (http://wiki.unity3d.com/index.php?title=Blend_2_Textures) that can blend between 2 textures that has a 'Blend' property that you can manipulate through code. How can this be extended to accommodate arbitrary numbers of textures in real time through code? Is this not the right way of going about this?

Another method I can think of is to just use the 2 texture blending shader and then just switch the textures so once the blend value reaches 1 (now texture 2 is showing 100%) delete texture1, set texture1 = texture2, reset blend value to 0 and put texture 3 as texture2 and repeat the process - This seems a little overcomplicated though