So every level i get these special units.... where are they???????

I dont see them for hire and i dont just get them so..... where the heck are they?

For every brilliant/decisive victory, there is a 10% chance in Panzer General 2 to get a prototype unit awarded. If you don't get one, the 10% carry over and the next time the chance will be 10% + 10% = 20% to get a prototype (and if not, afterwards 30%, etc).