Want scan-only virus removal, not real-time

I'm running Little Snitch to catch real-time transmissions, but I do want to scan at off-hours for latent problems. Which of the best anti-virus products support scan-only with all real-time checking disabled? I was running Sophos but their real-time checking cannot be 100% disabled despite turning it off (they confirmed, and you can see it running non-stop in Activity Monitor, and it was slowing down development). Thanks.