I like the chaos pollution idea, devonapple. You could go with something completely random. Doors would warp out of shape and can't be opened, small things spontaneously combust, change color, solid objects suddenly melt, you get the idea. I think living things should be able to be affected by this as well, only not to a degree that would cause any damage or pain. Change of haircolor for example or rapidly growing mustaches to make it a bit ridiculous.
Of course one of the bigger questions is: how common are wizards in that world of yours? If half of the population are wizards, that would be really unpractical. The fewer there are, the more severe the hexing can become, I think. And if your wizards are not able to use the magitech, they have a slightly less advantage over any normal folk, if you want that. In that case though, normals would be able to create magitech, which might not be what you want.
Just now I remember something: You could tie a specific hexing effect to the wizard that is casting and make it unique to his character. I know of at least one system that did something similar, but I can't for the love of me remember the name. A hotheaded wizard would heat up the air around him, maybe even make it smell like sulphur, a druid would make the plants around him grow as a side effect to his magic, an earth mage would create cracks beneath his feet or even small earthquakes, if his magic was strong enough. Wouldn't suit the dresden files, but maybe it is something you can work with.
Oh and Edison could still have invented (or at least perfected) the light bulb crystal. He might have just been a thaumaturgist instead of a physicist. I kind of like it when fundamental magical theorems are named after famous physicists, but I am a physics nerd.