That question of targeting is important: I would argue that the most effective way most companies support open source is by buying Red Hat or Ubuntu licenses simply because it's a model which every accountant understands and you can make a single payment which will filter to tons of projects either in the form of direct employment of maintainers or patch contributions.

I'm aware of various attempts to collect payments or offer support plans but I don't think anyone's hit a combination which is as corporate-friendly. Everyone understands the idea of paying for support and it's usually much easier to give six figures to one party than 3 figures to a dozen projects, _especially_ when the latter doesn't get you some kind of guaranteed benefit easily explained to the accountants.