Re: Renaming kits
To the first question, there are many reasons. Back in the day companies used to do it because one store might have a no compete clause. So store 1 has a clause that they are the only ones that can carry brand a. So The company makes brand b so that store 2 can carry those.
Another reason in modern day times is that sometimes brands don't want their name in certain places because it creates a negative stereotype. For example maybe Alesis doesn't want their stuff in WalMart because then real musicians will automatically associate the brand with junk because it's not at a real music store. So they have their cheap stuff also as Ion brand stuff that can be carried at WalMart. The normal person doesn't associate the two.
As alparrott said, the last reason is that they don't make it in the first place. This happens more often than you think as well.
To the second question. Alesis used to make a set that didn't have a module, just a in/out box that converted to USB/MIDI so you could use whatever software you wanted. It was pretty inexpensive, but I don't know if they make it anymore.
Amateurs practice until they get it right.
Pros practice until they can't get it wrong.