Do you mean a real executive position or a startup "technical cofounder" role?
I suppose, just the matter of preference. Personally, the startup option seems to be more appealing to me.
Your best bet is to tap your personal network.
That's what I figured. But there have to be some online resources for this specific purpose. Actually, after performing an initial search -- there seem to be too many of them already. Wondering, which ones really work, and what to avoid.