Blocking all the .cn IP address blocks appears to have been pretty effective. Still seeing a lot of traffic, but all they get is a 403 error.
Bandwidth used is back to normal levels, around 70 MB/day instead of 1.5 GB/day.
Despite with having 3000+
Deny from directives in the .htaccess file, blog performance actually seems to be better. The problem with chronic 500 Internal Server Errors has gotten a lot better since I put the block in. Not having to handle all those bot requests seems to have really helped.