When Summit Entertainment hit it big with “Twilight,” it followed up almost immediately with plans for three more films based on the Stephenie Meyer novels, with the sequels seen as a good bet for a B.O. windfall.

But even amid its heavy investment in the teen-friendly saga, Summit is trying to avoid the temptation to turn its slate into all vampires, all the time.

The mini-studio is sticking to its original strategy of releasing and distributing 10-12 films per year, including eight inhouse productions, with a focus on the mid-range films that the majors are less likely to greenlight.

The company is mindful of the pitfalls of shifting an overall strategy for the sake of quick success.

“History’s great for that reason,” says Rob Friedman, who heads Summit along with Patrick Wachsberger. “There are bodies buried everywhere in Hollywood from places that changed their focus once they had some success.”

Before Summit released “Twilight,” it had a string of five consecutive disappointments. But the company’s approach got another recent boost with the success of Nicolas Cage starrer “Knowing,” proving, says Wachsberger, “we’re more than just a one-trick pony.” Another reason for this stick-to-their-guns approach has to do with the message Summit is trying to send to the Hollywood community: “Our idea was to eliminate the silos and involve the various disciplines in all of the decisionmaking,” Friedman says. “Studios are great, but as you stay at a studio, you wind up doing more administering than anything else. So we’re telling people that they’ll be able to do more of the creative work that made them fall in love with the business in the first place.”

Summit is keeping its pipeline going with an eclectic mix, mostly in the $20 million-$50 million budget range. Aside from the third “Twilight,” the most likely projects to hit the screen in 2010 and 2011 include a rebirthing of the “Highlander” franchise; DC Comics adaptation “Red”; romantic fare including “Memoirs” and “If I Stay,” the latter directed by “Twilight” helmer Catherine Hardwicke; comedies like Steven Brill’s “Parental Guidance”; the time-travel sci-fier “Arena”; a remake of Korean thriller “Seven Days”; and a Harry Houdini biopic.

Over the past two years, Friedman and Wachsberger have transformed Summit from a foreign sales company into a full-service production and distribution studio, and their timing has been fortunate. Friedman, who had most recently been vice chairman at Paramount, came aboard in April 2007, as Summit announced a $1 billion financing deal with Merrill Lynch and a consortium of investors.

“We would not be able do that deal now,” Wachsberger admits. “The appetite for our movies is the same but the financial climate is completely different.”

The backgrounds of Wachsberger and Friedman are a study in contrasts. Wachsberger, a Frenchman, is a calm, courtly man who speaks softly with a distinct Euro accent. His expertise is in the international market: As a young man he was a partner in a small Brit-based production operation that focused on the overseas territories. He’s spent the last 25 years making the rounds at Cannes and the AFM, selling foreign rights to projects on the upper end of the independent scale.

Friedman, cautious in conversation, is a veteran of buttoned-down Hollywood studio culture, having logged many years with the Daly-Semel machine at Warner Bros., where he was chief of marketing and PR, before moving to Paramount.

“When we started this company, we were focused on hitting singles and doubles,” says Friedman. “We’ve hit a home run with ‘Knowing.’ ” The sci-fier has grossed $78 million in the U.S. and $144 million worldwide.

Achieving success has demanded patience. Summit’s first five releases — “Fly Me to the Moon,” “Never Back Down,” “P2,” “Penelope” and “Sex Drive” — hardly lit the box office on fire, with a combined domestic cume of $60 million. The situation was dire enough that last fall, Lionsgate and Summit held informal merger talks.

The discussions didn’t lead anywhere, partly because it was becoming increasingly obvious that Summit had a serious hit coming in “Twilight.”

Friedman admits that Summit got a big break last summer when Warner Bros. decided to delay its sixth Harry Potter pic from November to July — turning “Twilight” into the de facto youth event movie of the fall season.

In its first weekend, “Twilight” grossed $69 million, more than the combined gross of all other Summit films. The pic has grossed $191.5 million domestically and is nearing $400 million in worldwide grosses.

“I anticipated it would do maybe $100 million domestically,” Wachsberger admits.

Now that “Twilight” has launched a reliable franchise, Summit has established a measure of security — much like Lionsgate has with the “Saw” and Tyler Perry titles.

The second pic — “Twilight Saga: New Moon” — is due out Nov. 20, and the third, “Eclipse,” opens June 30, 2010. No release date has been set for the adaptation of the fourth and final novel in Meyer’s series, “Breaking Dawn.”

But Summit is also plotting more romantic comedies, particularly those with international appeal — less like “Forgetting Sarah Marshall” and more like “Four Weddings and a Funeral.” Meanwhile, it’s enduring the inevitable flood of ideas for other bloodsucker pics even as it seeks to stake a claim on a more diverse slate.

“When ‘Twilight’ broke out, we got a lot of vampire scripts,” Friedman says, “But ‘Knowing’ has really confirmed that we’re doing a broad range of projects and that we’re not a genre company.”