First question - what specifically are you looking for in a ROM?
Putting a custom ROM on a device just so you can say you have one is bad for 2 reasons:
1) It voids the warranty.
2) You can mess the device up when flashing a ROM - you can even permanently damage it.
If there's something specific you're looking for in a ROM, there may be one out there that meets your need. (And, yes, every phone and tablet needs a specific version of any ROM. There's no phone or tablet that can take any ROM, and there's no ROM that can be used by any device. Your tablet is no different than any other one as far as that goes.)