It's easy enough to get un-rate-limited. Just build up a track record of making substantive, curious contributions—that is, of using HN as intended—and then ask us at hn@ycombinator.com. It's not as if we're unresponsive (although the inbox does have poor worst-case latency).
Actually we often take rate limits off accounts without being asked. It's a matter of looking through the history and seeing if the account has stopped taking threads further into flamewar and/or is no longer making a habit of unsubstantive comments.