There is no cheat code that does that but there is a mod a mts2 permitting you to do that.
Unfortunately, it has not been updated for the Pet or Seasons ep.
I think someone asked for it on this site not long ago. I am not using this mod and do not remember who made it unfortunately.
Which would explain why I was having such a hard time finding it. I was searching for cheat codes. Oh, well; I'll just find a lot the size I want, level it, then start putting stuff on it.
Thanks, MissDoh!