I made a new bounty, which is for 6 BTC! Only applies to CUDA miner though.
Hello! This bounty is for a working, good-speed implementation (faster than a cpu of equivalent price by a few times, at least) of a primecoin miner for GPUs. Either CUDA or OpenCL is fine.
Requirements: Binaries for windows and linux, as well as source code released publicly.
If any mod (or admin!) would be open to holding the escrow account for this bounty, I'd be happy to send over my 400XPC and post that address in OP so others can donate.