At the same time, seeing how you handle version control, how you deal with contributors and bug reports, all that matters. Being able to see that is much better than taking one's word for it.
So yes, as someone who previously worked on a shop where no code would get out, I can relate to the feeling. But the above is still true. A few things you can do about it:
- open not the products you have entirely, but modular parts of it.
- should the previous suggestion not be an option, get the company to run a blog, and have you/your workmates share solutions at a discussion level.
- get the company to allow developers to work 10%, or 20% of their time, on open source. It'll help keeping you guys sharp, at the same time it helps you putting a name out there.