How many of these cold emails have you sent? To what extent have you varied the copy in those emails? Are you just asking for something, or are you offering something as well? Have you gotten advice from other successful hustlers (concretely, talk to some seed stage founders for hustle ideation; abstractly, read How to Win Friends & Influence People at least once per year) on what you might want to put in the email?
What about non-email channels? Have you gone through Twitter (This is how I've met multiple investors and advisors, totally cold, with no friendly introduction.)? How about crawling toward them meticulously through LinkedIn? How about networking via HN? Have you tried hanging out on relevant IRC channels? Have you contributed to their questions & answers on Quora?
I don't mean to be overly critical here. The OP is a great example of inbound marketing hustle, and I commend you guys for it. Two of the key ingredients in startup success are determination and resourcefulness. Clearly you're resourceful, now crank up the determination a notch. Right now it sounds a bit like you've found good excuses not to keep trying. If you can't land a Skype call with someone who might be able to help you get noticed by YC, what evidence do we have that you're going to land a Skype call with a key distribution partner in six months?
Keep trying. Keep swinging and striking out. You'll see patterns. You'll improve. Eventually, you'll start making contact.
You know what takes savvy and elbow grease? Creating a customer acquisition channel! There are just so many amazing technologies these days for finding people and getting their attention. You could pick a YC company and find a way to generate credible leads or affiliate customers. You could do this with a completely automated, partially automated, or manual solution (like a series of great blog posts). There are all these YC companies who are making new products that replace existing ones. Take a special look at the B2B products. They have limited ability to directly target more than the few most lucrative verticals, but you and your friends are probably intimately familiar with at least one industry that could benefit from a new technology.
Here is where the most critical attribute of a YC-worthy person come in: hustle. It's all out there waiting for you: pick a technology that can help an industry that you understand, and sell that technology to them. Increase their bottom line demonstrably. After you've done this, you'll probably find you're a lot less interested in getting into YC, but they'll be more interested in you.
I'm confident there is at least one YC alum who would respond to your cold email. Stop assuming you can't solve this problem, and solve it.