Logo for Construction-related web company

We are looking for a logo to head the branding of our professional-services company servicing the construction industry. This logo will be used across our website, stationary and other documents we'll need to distribute to clients, and the colours used in the logo will form the palette for our web application.

Constrex

Constrex will be providing services to major construction companies, and how they deal with their subcontractors. As such, we'll be involved in multi-million dollar transactions, where the costs for getting things wrong can be extremely large (both for us and our clients).

Because of this, we want our brand to communicate that we are a professional, dynamic company, who are able to connect our clients with the subcontractors they need to successfully execute their construction projects, and who they can trust to get things right every time.

Some things we'd like to see in the design (but please feel free to explore other ideas you think might work)- The logo should be strong, sharp and eye-catching. Think clean and modern.
- Blue palettes seem to work well - they've been what we've used for the internal work so far - but this is by no means a requirement
- The logo should work as both a full-color design used on web-sites / CMYK printing, but should also be able to be reduced to a single colour, and to small sizes
- Either Constrex or constrex (without the capital C) is suitable
- After the winner is paid, we want the winning design as an Adobe Illustrator .ai file, as well as font files for any fonts used in the design. (If there are licensing issues with the font files, we can discuss this).

No tacky images of construction equipment or builders or anything which will cause me to think of "Bob the Builder". As a company, we're more about connecting companies with each other, than the act of constructing a building itself. No tag-lines. No use of clip-art, stock images etc unless you created them.