I'm with EJ12N and Burn on this one.
I used to work in Visual Studio, then one day I started using SlickEdit (at a new job). SlickEdit has a very similar functionality, which everyone at my previous job used.
Ever since I started using it, I've never felt much need for a project panel.
On the contrary: Almost every editor I've ever used doesn't have a quick panel, which is so important to me (especially for large projects) that I abandon most other editors. This is one of the reasons I love Sublime so much.
That said, I suppose a project panel which slides in and out of the left side of the screen wouldn't be all bad.
The way I picture it, it would look like most editor's project panel, except it would have a quick-search field at the top which works the same as "Open file in project". That way, you get the best of both worlds, and people who haven't seen the light yet get a chance to learn about this great feature.