Someone who has a pending comment will have to wait till it goes live to post another. We're hoping that good comments will get endorsed so quickly that there won't be a noticeable delay. Is there some timeout? If not, commenting on a several-day-old thread will guarantee that you can never post another comment, since once threads drop off the front page it's not likely that many 1000+ karma users will even see those…
Hmm, trust cperciva to find the thing I'd overlooked. I'll add a pending page that collects pending comments. Maybe that will solve the problem.
(newsop pending () (pending-page user))
(newscache pending-page user 60
(listpage user (msec) comments* [if (and (cansee user _) _!pending) _]
"pending" "Pending Comments" "pending" nil))
In this project I've really benefited from having kept the code tight.