The OP wrote that "I prepared a DMCA and sent it via fax to Softlayer. I never heard back and finally gave up on the whole thing."

This is probably not the most effective way to handle a DMCA notice. While it would be nice if every company's compliance team was responsive and open, this task is often outsourced and because the DMCA is fundamentally a legal process, review and action can be very conservative. If you want to fast-track action, certified or registered mail beats facsimile every time. A follow-up letter including a copy the certified delivery receipt is very effective. This is even more true if it's on law firm letterhead or company letterhead and professional in tone.

Presumably, if this is a big enough issue to post on HN and if there's some lost revenue, it's probably worth the time to follow up on the DMCA takedown request(s). It may also be worth the time to ask an attorney to prepare a sample letter you can use for this and future takedown procedures.

I'd encourage the OP to not give up on the DMCA process, as it can be very effective with a little bit of followup.