To throw a point out there, fogbugz/Jira quickly starts to "grow" into the 1000+ range once it has over 20+ users. The key though is that they usually start as

To throw a point out there, fogbugz/Jira quickly starts to "grow" into the 1000+ range once it has over 20+ users. The key though is that they usually start as something used by a small group of folks and then grows as more folks realize it has some niceities over the open-source solutions. It also means however that Fog Creek/Atlassian do have a sales force that will call you over the phone, personally answer your questions, and sometimes negotiate on price.