Here's some code: https://github.com/KhronosGroup/OpenGL-API/issues/46 But yeah, GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS limits usefulness of that.
I wanted to say that with some compiler hacking it should be possible to lower SPIR-V using GL_EXT_buffer_reference into bindless image loads, but SPIR-V doesn't have standardized bindless texture, duh!