This is what I've been doing recently. Hasn't resulted in any sales yet, but I've had emails back from the folks I target, so I know I'm reaching the right people.
If you have generic keyword names, do a Google search on the exact match and see who's advertising using adwords. For each advertiser, follow the link to the corporate site, and look for the list of executives (usually under the About link. You want to target the VP Marketing and/or CEO. Look through press releases on the site to find an email address for someone who works at the company - PR folks usually list their emails so journalists can reach them. If no email is listed, but you find the name of a PR person, do a Google search for exact match of their name + company.com and see if the email address turns up. Once you have the format of the corporate email, you can put together a pitch and email it to the VP and CEO.
After running through all of the adwords advertisers, do the same thing for all of the corporate sites that come up on an exact match search. Well, maybe not all, just the first few pages. Then see what happens.
Not so sure about non-generic keyword domains. If you have 3 and 4 character acronym type names, you might do a search and see if any corporations or products match the letters and then do the same email harvesting process.