Any way to partition wp_options?

No, and I strongly advise against changing the WordPress Options table schema, you’ll run into many problems such as:

  • No longer having a reliable update process
  • Non-portable code
  • You won’t be able to use the get_options suite of functions and the object caching and optimisations that come with them

If you managed to get it working with get_options you’d be back were you started

My suggestion? $prefix.'_option_name'