Is there a simple way (prebuilt command) to add a bunch of meshes (nodepaths) together, combining all vertices and textures? I basically am wondering if there is a way to create say two different geoms procederally, and then put their verticies together so that when rendered they are sent through the pipeline as one bigger mesh and not two?
Yep.
Put them in 1 nodepath then call:
nodepath.flattenStrong()