I am giving this a try but for some reason it keeps complaining about authentication error as soon as it finds new shares:
[hashkill] Version 0.2.5
[hashkill] Plugin 'bitcoin' loaded successfully
[hashkill] Found GPU device: Advanced Micro Devices, Inc. - Cayman
[hashkill] Found GPU device: Advanced Micro Devices, Inc. - Cayman
[hashkill] Found GPU device: Advanced Micro Devices, Inc. - Cayman
[hashkill] GPU0: AMD Radeon HD 6900 Series [busy:13%] [temp:41C]
[hashkill] GPU1: AMD Radeon HD 6900 Series [busy:0%] [temp:36C]
[hashkill] GPU2: AMD Radeon HD 6900 Series [busy:0%] [temp:44C]
[hashkill] Temperature threshold set to 90 degrees C
[hashkill] This plugin supports GPU acceleration.
[hashkill] Initialized hash indexes
[hashkill] Initialized thread mutexes
[hashkill] Spawned worker threads
[hashkill] Successfully connected and authorized at mining.bitcoin.cz:8332
[hashkill] Compiling OpenCL kernel source (amd_bitcoin.cl)
[hashkill] Binary size: 203728
[hashkill] Doing BFI_INT magic...
Mining statistics...
Speed: 976 MHash/sec [proc: 10] [subm: 1] [stale: 3] [eff: 10%]
[error] (ocl_bitcoin.c:318) Failure connecting and authenticating to server mining.bitcoin.cz at port 8332!
[error] (ocl_bitcoin.c:326) Retrying in 20s...
Speed: 0 MHash/sec [proc: 12] [subm: 1] [stale: 6] [eff: 8%]