Keep in mind the GUI will not display vApps VM's on layout screens if they have more than some number (trying to find the number again, but I think it was around 28?)
Also if making a VERY large vApp you might want to look at why it is being done - vApps in many systems should start quickly, and only contain what is needed to run that vapp that would not be shared. - Sometimes a large vApp should really be a OrgVDC (not always, but at least know why a vApp is getting that huge)
