I don't know Wisconsin law, but under federal law, the answer is yes, but have a lot of money. Since the 1986 law "froze" machinegun registration, the prices of legally registered guns have shot up astronomically. I haven't checked recently, but not long ago the rock bottom for a registered automatic weapon was around $6000. Very desireable guns, like Thompson M1928 SMG's are going for $15000-20000. We used to worry about the $200 federal transfer tax; today that is insignificant.
Jim