Ask HN: Finding sponsorships for dev user groups (& other user group questions)?

About 6 months ago, I started a monthly dev meetup in South Bend, IN. We have decent attendance (20-30 people each month), and I have managed to attract half a dozen local corporate sponsors, as well as securing giveaway sponsorship from both JetBrains and O'Reilly. I'm hoping to take the group to the next level, and I'm looking for advice on a couple of items:

- What are some other great companies to pursue sponsorships from (either monetary or product giveaway)? - What is the best way to find companies with dev evangelists who would want to come talk to the group? I try to source the majority of our content locally, but I think people also value guests from outside the local community. I have had a few from Microsoft, but I'd like to diversify our guest speaker pool. - We're currently held together by a bunch of handshake agreements, and I'm planning to incorporate it as a non-profit. Any tips or cautions on this process? This is all new ground for me.

I appreciate any help and wisdom you guys can provide. Thanks!