Zombeavers was too goofy for you but the concept of zombie critters is appealing, you could do worse than Mulberry Street (2006), which is about zombie rats. After all, beavers are essentially the nicer, more respectable cousins of rats; they both have distinct tails and prominent front teeth. Beavers are inherently kind of goofy looking, so it makes sense their zombies movie would be a silly parody. Rats are inherently dirty and nasty, so it's fitting that their movie would at least aim to be serious and scary and have a deeper thematic meaning.
Mulberry Street centers on a hodgepodge of residents in a New York slum apartment. The place has been bought out for a gentrification project, but on the day the residents receive their eviction notices, a virus spreads through Manhattan, carried by the rats. Once bitten, victims turn into carnivorous, rampaging monsters, complete with pointy teeth, ears, and claws that help them chew through the walls.
This is a zombie movie not set in a suburban mall or the post apocalyptic countryside. Even before the zombies turn up, this part of New York already looks like the Four Horsemen rampaged through it. This is a grim, grimy, filthy, dank setting, a place where disease-carrying rats can easily move and flourish. The rats never kill anyone directly (they never swarm and devour victims like the beavers do), but they are carriers for a deadly disease.
Meanwhile, the country invests in overseas wars at the expense of investing at home, leaving its scarred veterans, represented by Casey (Kim Blair), to return to a dilapidated neighborhood. Yet, the rich and the powerful have no problem forcing people out of their homes for a new development or fleeing when the shit hits the fan (in a funny moment, a radio announcers the mayor will give a press conference from Bermuda, this after the mayor insisted there was no cause for alarm). Would these rats have been able to spread if years of neglect and exploitation hadn't created a perfect breeding ground for them?
While the neighborhood might be skid row, it is just that: a neighborhood. Sure, their living conditions are cruddy, but these characters have each other, and they are a quirky bunch, and they're good, honest folk. There's Clutch (co-writer Nick Damici), a widower and former boxer waiting for the return of his daughter Casey; Coco (Ron Brice), a gay black man who's close enough to Clutch and Casey that he can refer to Casey as "our little girl;" Kay (Bo Corre), a single mother with a teenaged son and who seems to have a thing for Clutch; Ross (Tim House), the hardworking super; and Charlie and Frank, a World War II veteran and his son who have lived in the same apartment for fifty-plus years.
Sounds like I'm describing a great movie, right? Well, the material is there, but the execution is iffy. There are some great shots of people being dragged into dark alleyways, and I don't recall another zombie movie that emphasized the sounds of chewing and eating so much (it's pretty disgusting to hear but not in a gratuitous fashion). But man, so much of the movie is visually incomprehensible that I couldn't tell what has happening or whom it was happening to. The camera moves and shakes too much, the editing could be charitably described as over-caffeinated, and sometime's the film is just too plain dark to see anything.