What’s Microsoft CEO Steve Ballmer going to do next?

That’s a question that folks around Seattle are wondering after the boisterous software executive announced that he’ll be moving on from the company he’s worked at for 33 years. We speculated on a few of possibilities in our post earlier today, noting that there’s a chance for him to get more engaged with the startup community, philanthropy or bringing back an NBA team to Seattle.

Now, at least one Seattle entrepreneur is taking things into his own hands. Yabbly founder Tom Leung today started a petition, pleading with Ballmer to create a $500 million seed fund for Seattle startups.

A $500 million fund is pretty bold, even for a guy who’s got an estimated net worth of $15.2 billion. After all, that’s double what Amazon.com founder Jeff Bezos just paid for The Washington Post. That said, Ballmer and financier Chris Hansen’s failed plan to buy the Sacramento Kings totaled about $1 billion, when factoring in arena costs.

In our post earlier today, we were a bit more modest, suggesting Ballmer could funnel $100 million into the startup community.

Leung writes in the petition:

You could get as involved as you like or hire a few partners from existing VC’s in Seattle, SV, and NYC (ideally a mix) and have them run the show day to day. This is the kind of bold, game-changing bet that could have massive repercussions for Seattle and the country. Focus would be on the space between angel funded and Series A (call it $1-2M rounds) and help us create the next Microsoft or Amazon.

Some notable folks have already signed the petition, including angel investor Rudy Gadre; Moz CEO Rand Fishkin; and attorney Craig Sherman.

I asked Leung why he felt compelled to start the petition, and he said that it just felt like a huge win-win for everyone.

“Ballmer gets an opportunity to help out his local community, the country’s tech industry, and leverage his expertise and resources,” says Leung. “Seattle gets a ginormous shot of adrenaline that would seriously put the town on the map once and for all when it comes to full-stack tech ecosystems. Seattle startups get access to runway to take bigger bets, dream more audacious dreams, and experiment like mad.”

As I’ve noted before, Seattle’s startup and venture community is at a crossroads. There’s an opportunity to supercharge efforts, providing additional fuel to new startup ventures, and making sure that young entrepreneurs want to grow their businesses here.

I, for one, am not convinced that there’s adequate capital available, especially as some traditional venture capital firms in the region (Frazier, Ignition, OVP) have scaled back or closed up shop. Seattle’s market share of the total venture capital pie has remained relatively stagnant around five percent.

Ballmer’s cash certainly could help?

What do you think? Would you rather have $500 million going to new entrepreneurial ventures or a new NBA franchise?

Well, I guess the good news is that Ballmer is rich enough to do both, since two $500 million bets would amount to just six percent of his net worth.

Meanwhile, here’s a look at Todd Bishop and I talking about the Ballmer news in a special version of our podcast.