Well, there is Minefactory Reloaded. Not sure the release in Ultimate has the block you need(fairly certain it doesn't, in fact), but it has a block called a AutoSpawner. It's somewhat similar in of that you get a item, put it in the spawner, and when given a redstone signal craps out entities like a white person eating salad in Mexico. The difference is unlike Soul Shards, you need a fuel source for it. Pump in Liquid Mob Essence(which is obtained from killing things with the MFR Mob Grinder) and give it a filled Safari Net, and you get more mobs. The problem is you need a decent amount of Liquid Mob Essence to run it for a decent period of time(I think more then what you would get from ramming mobs into your Grinders from the Autospawner), and of course, it requires energy to run as well.(#FirstWorldProblems)
The good news is it is great for villager spawning.(grab a useless villager with a safari net, set up a AutoSpawner, and crap out villagers until you get the one you want)
If you catch a pink sheep and want to clone sheep you get all colors as well, actually, unless you hit the button which makes it only make entities with the same data flags(so only pink sheep, for example, or only blacksmith villagers). It doesn't save their inventory, though, to prevent exploits.(so you can't find a zombie which can wear armor, give him full diamond and throw a Iridium Ore for him to hold and crap out zombies holding all these items if I understand correctly)
