If you aren't doing consulting, this model is not open to you. But if you can't consult, you probably can't sell product either. This is like asking, "if you're a business guy who just needs a web guy to implement his idea", &c &c.
On the other hand - if you are lucky enough to run into people who are better at executing than you are - then funding them seems like the smartest thing to do, should they want to work with you that is.
Contribute to your product offering as much as you can. Participate in discussions. Talk to customers. If you're lucky, your consulting customers and your product prospects will overlap. Over time, ramp up revenue so that you can wean yourself off consulting.
This attitude that there's some status hierarchy of kinds of people in a startup is toxic. Working companies are comprised of people who will move mountains to get stuff done. You can spend tons of time pushing on the mountain of external funding, or you can push on the mountain of getting immediate and comfortable levels of cash from consulting. Both have their upsides and downsides. Either way: you're going to have to do stuff you wouldn't otherwise want to do.
Not necessarily. I product manage http://decalcms.com/ but don't really do much of the "actual work" on it until it's time to do a release at which point I focus a lot on the marketing.
The rest of the time I drum up business, run game on support and client queries and generally keep things ticking over.
Since I do have (too many) ideas, but didn't like any of them enough to commit myself to it - the plan was to build a dream team (I have a knack for leading people - The Right Way(tm)) - and just practice execution until a killer idea in a good scalable market came along - and then run with it.