I have moved a few buckets of TInker's blue slime water into my mob spawner. Blue slimes spawn from it routinely. I get a consistent supply of blue slime I can use for jet fuel that way.
Our server also added two crafting recipes for slime. One with leather, a bone, and a bucket of water, the other with a block of flesh (9 zombie flesh), a bone, and a bucket of water. We reasoned that slime must be similar to jello made from keratin, and that process if fairly straightforward on Wikipedia. Leather was a quality ingredient and cows grow slowly, but zombie flesh is everywhere and you had to supply more.
We added these because we have finite water and one of the first tech tiers was to reach iron for iron buckets because wooden buckets don't take heat, and then you can use iron and slime to craft Railcraft water tanks which slowly generate water.
RoC has dependencies on slime and dirt, and no way to make either... I'd argue that eventually a boring machine makes dirt easy, but otherwise without Tinker's you would need a vanilla slime farm.
You can make dirt from compost.
(Actually, is there any other use for compost? Does it work as a bonemeal equivalent or something? The only use I've found so far is in a dirt crafting recipe...)
I think with Tinker's you can also set up a system through which zombies are spawned from a Powered Spawner and fed into a smeltery for blood. I thought you could craft magma cream from blood balls, someone correct me if I'm wrong on that.