I managed to get multitexturing working, and i'm pretty happy with the results. I now have an alpha map texture, which is used to "stamp" the new texture on top of the existing base tile. With the addition of texture splatting, the old system of blending tiles with their neighbors is thrown out the window, seeing that texture splatting can take care of this for me now. If you would like to use splatting as well (without shaders), I have included code to do this with or without the use of vertex arrays (see here).

In a nutshell, I am just replacing the alpha values of a texture with the alpha values in my selected alpha tile, and attaching that texture to a quad which is rendered over top of the base texture. An example:


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