Accessibility Consultant Guidance

I was wondering if anyone had a recommendation for third party consultation / certification of compliance for particular software.  My company is a SAS solution and we have done a lot of work based on the WCAG guidelines, but was wanting another set of eyes.

I contacted a couple of third parties about reviewing our site, but each only specialized in a given industry vertical which isn't my software.  Any suggestions are welcome.  I have also reached out to WebAIM, but that is still pending.

Thanks!

Shane Broffman