Thanks for the advice, EditorOne. I've been trying to make myself write around 2k words a day, and for a solo project I got to around 10k, so that gives you an idea of how long that lasted for. But I agree with the theory, making writing a book a bite-size ordeal.
I think if I had an actual deadline to be afraid of, I'd (hopefully) be more productive as well. I'm trying to using NaNoWriMo for that, but it's not going well.
If you're interested, I'll give a brief history of my history, I'd be happy to hear any more advice about it from an INTP who's actually completed something!
Basically, I've been building on a huge horror/fantasy world here and there for a little over ten years. While talking to a friend of mine about wanting to write a book, he pointed me to a friend of his (ISTJ) that was experienced in publishing sci-fi short stories. After introductions, I went on to explain the world through email correspondence, over the course of two months (sadly, the most I'd ever written at that point), and he was really interested in working with me.
I sent him what I thought was a decent first chapter, and a week later he sends me his version of chapter one based off of my own. In short, from there I sent him summarized outlines/ideas for each chapter, one at a time, and he would write them in his own fashion. It's written in the first person perspective, and in the style of a journal or recounting (like Crichtons' Eaters of the Dead), and since he wasn't aware of what was going to happen next, it had a really neat 'here-and-now' effect.
He's on hiatus until his PhD studies are over, but I would LOVE to take over the writing (which he's okay with, as long as he's involved in the re-write). The main character is about to have an alternate personality take control, which would be perfect for me to start narration, but I want more experience before I try to fill his shoes.
So, I have a lot of short burst experience to do a solo project in small bites, but I don't have anyone but me waiting for anything to get done. Again, I got to 10k on my own solo book within the same story world, but there's not any urgency in it. It's not like I want to lean on anyone exactly, but it seems like I need someone that is expecting me to send them something in a timely manner. Thus, the desire to seek someone out to work with, brainstorm aloud with, etc.
Thanks again for your input so far.