Hi Shad,
Thank you for the quick response. Our case is less standard than that. Most of our business is from used industrial equipment. Because of the quick turn around and nature of our business model, we do not use leads. Now that we're getting more sophisticated with our marketing, this will probably change but that's a lot of planning and painful retraining away. For now, we are trying to automate the qualification process so any leads that get added through Marketo can be promoted to a more useable contact record.
From what I've seen of the duplicate detection rules, you should be able to set up a similar process to the salesforce conversion process, but a bit reversed. Essentually, you set up the duplicate detection rules to match the contacts and accounts as you need and, when a user tries to qualify a lead using the dynamics qualification, the rules will inturupt the process and allow the user to merge them instead. However, as I have said, we have not used it, so if you already tried and found it does not work as advertised, I'm sorry to hear that.
I can confirm however, that the out of the box qualification does sync properly with the Marketo. I tested using 1.0.0.11 and everything comes through. Our next step is going to be trying to cheat this process into a workflow by creating a plugin to call the QualifyLead request at the contact level. After we let this process create the contact, the rest of the workflow can find any matching accounts and update/create as needed. In our situation, Marketo is the only process adding leads to our system and they are already checking for duplicates based on email, so we can just let the contact level run, but it sounds like duplicate contacts can be an issue for you.