I am fanatical about testing and specifically about testing my marketing and one of the tests I am currently running is on getting people from a few key, related industries, to exchange links with me.
This is basically what I am doing.
I put out marketing to find people that would like to work with my clients that are not directly competing with me.
An example would be a tiny ad on my homepage that says "Add Your Business, Service or Product To My Local Resource Directory".
Then, I explain that my clients would benefit from having a great list of local providers and I'd be willing to list them there if they also linked to my website from their website.
It is a pretty typical link exchange request.
I was talking to a business associate of mine that was looking for ways to network and get more referral business from a certain industry.
I told him about what I was doing and how he could, with some very small modifications, set up a similar program to build a referral network.
They key, and what many business owners miss, is that you do need to actively market this exchange just as if you were marketing a product for sale.
Fail to market it and you'll fail to make a sale (in this case the sale is exchanging links).
In fact, I look at so similarly to how I look at making a sale, I actually track conversion rates on a squeeze page to get more information about exchanging links (and even blog about that, but that's a topic for another day).
You can, and I believe should, actively be doing something very similar in your business and to promote link building on your business website.