The Ruby requirement makes plenty of sense to me. But the Textmate/Heroku/rspec criteria make for a pretty tight Venn diagram, especially since you should be looking for someone who doesn't think exactly like you do. And do you really care if your roommate uses a different text editor than you do?
I've updated the website to say Textmate is preferred rather than required.
The "heroku ftw!" remark is just a deployment option that I added in there to express my feelings towards the company. Technically it doesn't matter what platform we work on. I just happen to find them to be a rather unique and creative service that suits my needs.
As far as RSpec - it's a matter of personal preference, but again... technically it doesn't matter.
Anyone who doesn't meet the requirements EXACTLY should not feel unwelcome in sending me an email :)