Hi Candice
I've only had a brief look at your site and your link profile, but while I can see you've made a solid start, I think the reason why you're not ranking is that you'll need to be doing more of what you've done already.
I can see a a lot of links from directories in your link profile. Personally, I would expect these to add a very small, if any, amount of benefit to your SEO, so I would focus elsewhere from here on in.
Content marketing could be a great strength of yours as you certainly look like an expert in your field. This blog post, for instance, is very thorough and in-depth. While I think guest posting on relevant websites is definitely worth your time, I think you should reserve your best content for your own blog and try and attract links to those posts.
The way to achieve that is to do marketing by more traditional means - get your message out there. Your social media presence is definitely going to help with this. But in the example of the blog post that I linked to earlier, could you maybe envisage something like that in the form of an infographic, perhaps? That way you could get people to link to your website by also sharing with them the image that they can post on your site. Or perhaps you can make it an interactive guide? I remember this guide on how to learn robots.txt with interactive examples - I can imagine something like that would be incredibly useful for your industry and would certainly get people talking about it and linking to it.
Similarly, tutorial videos hosted on your site can make a great educational resource that people will want to link to. And how about a Q&A resource? I'm sure that you'll get a lot of common questions from clients about certain drupal problems. You could fashion these into a really cool resource. It's a bit out there but have a look at this Q&A that the McDonalds Canada site has done. I can totally see an equivalent for your industry - you could utilise your social media channels as well and invite people to ask any questions they have on Drupal. It could really take off - just look at the links on that McD's subdomain. Big brand, obviously, but with thousands of links and hundreds of root domains you can see how many people like the resource. If you can create something like that for Drupal, the links are sure to flow.
Set up some alerts on twitter using RSS feeds and IfThisThenThat that will trigger when someone asks a Drupal related question. You can hit them up and say you've answered the question on your online resource - this may encourage more links. Similarly, Pinterest could be a great channel for you. Showcasing the best or most visually pleasing Drupal sites on a public board could be a fun idea.
It's gonna be a bit of hard work, but I think you've made a great start to the site already - it's now a case of scaling these methods up. The great advantage that you and your team have is your expertise and the fact that you're already producing excellent content. If you can market those out in different ways and encourage people to see you as an authority resource, as well as an excellent service, then I think you could go really, really far.
Hope this helps Candice! Give me a shout on Google+ if you fancy chatting some more.