so as for different roms saying they are for different carriers, they are most likely just referring to having the different directories (/folders) for the carriers. so what that means is that a sprint rom would actually work just fine for you, but it may have things like sprint tv or on demand on the cube or other places. it will still function just fine and everything though. it would probably look a little different than the stock vzw rom (im not sure really how it looks) and such. the only way that you could get screwed having the wrong rom for your carrier is if you were flashing the radio as well. but since you're not (in most cases), it doesnt matter really. just be sure to check the roms threads about whether they include a radio or not.
so what you will need to do (for verizon -- replace refs below for your carrier) is:
1) download a
kitchen: set of tools for creating/editing roms. dcd just finished his vogue kitchen; available
here on xda in this vogue upgrading subforum. there is also lattisimo's older vogue kitchen available on the ftp site at ppc geeks ("qlinks" at top of page, ftp upload/download, vogue -> users -> lattisimo? (i think?)) (INSOL EDIT: could not find lattisimo -- but the list of users is here:
ftp://up.ppcgeeks.com/Vogue/Users/.
2) download a verizon titan/mogul/ppc 6800 kitchen from somewhere, look in the "sys" folder contained therein, and copy the "carrier vzw" or "verizon" or "carrier customizations - verizon" folder (it will be something like that) into the "sys" folder of the vogue kitchen you have downloaded. (INSOL EDIT: Titan kitchens can be obtained here:
ppckitchen.org
3) delete whichever other carrier customization was already in that folder in the Vogue Kitchen (such as alltell or sprint or bell etc..)
4) run "buldit.bat" or "buildnb.bat" (or something similar) and flash your new rom that will be located in the "ruu" folder after the batch file (xxx.bat) is finished!
feel free to ask any more questions if that wasnt too clear (sorry :S) .
good luck!