So, at ~10k seeds/minute... maybe ~1677 minutes to go through the full search space (only 4 words per slot, 12 slots)... which is around 28hours. 
The main slow downs will be:
- More words in a given position... that's going to ramp up the total search space
- Actually generating private keys/addresses to check, as these are computationally a lot slower than just checking if a seed is valid.
With some optimisation, and maybe porting to C or something faster than Python, you'd probably gain some performance benefits...
If you are ONLY validating the checksum of each permutation then your speed must be in the millions per second rate. 10k is way too low for that because essentially you are just computing SHA256 (for BIP39) or SHA512 (for Electrum) and your CPU is capable of computing millions per second of these hashes. Translating your code to C shouldn't change much about its speed because the slowness is most probably in the algorithm you are using not the language.The main slow downs will be:
- More words in a given position... that's going to ramp up the total search space
- Actually generating private keys/addresses to check, as these are computationally a lot slower than just checking if a seed is valid.
With some optimisation, and maybe porting to C or something faster than Python, you'd probably gain some performance benefits...