sftriman - 4:57 pm on Apr 3, 2012 (gmt 0)
Update: it's been 5 days, and my search.php count in the Google index is now 2,900, down from 8,000. Using the search: site:mysite.com search.php, which is what I used before and now.
At the same time, the total indexed count has gone up to 31,300. Traffic has remained the same.
I wrote code to "smart" 301 redirect to category or brands pages based on the keywords. Where my logic doesn't provide a target page, I've hard-coded the new mappings, about 400 in all so far. About half those 400 keywords (phrases) map to "nothing" - that is, I let those pages 410.
I checked Google for my new look.php search page, and thankfully, none have been indexed so far. So let's see what happens 2 weeks from now - I'll check in again.