GL_TEXTURE_2D_MULTISAMPLE and sampler2DMS

Not at the moment. Currently, you can bind a 2D texture to a multisample FBO, which causes Panda to render into a multisample renderbuffer and then resolve it back into the regular 2D texture after rendering. This is usually adequate; it might be in your case too, I don’t know. Multisample textures only become relevant if you want to postpone the resolve.

However, multisample textures sound like it would be a fairly simple feature to implement. Would you be interested in contributing this feature yourself?

If not, no problem. Perhaps you could add this request as an issue on GitHub?