I looked at the Midwest playpen, but i am wondering if that is a lot of
wasted space, but the plastic bottom was nice.
 
In reguards to the midwest cages, there is the typical 3story ferret cage
available for @$200 in my area,Charlotte.  There is also a smaller cage
available built to house cats, also by midwest and you can purchase the same
shelf and ladder that comes in the larger, more exspensive version.  I have
2 shelves and a ladder and 1 ferret, Bilbo.  There is plenty of room for the
hammock and several toys, a litter pan and I'm sure this would accomodate
your 3.  It is exactly 1/2 the size of the larger 3 story cage and is $100
also if one of your little fuzzbutts fall off the top shelf the distance
isn't as far and the door is large enough to clean and reach around
everything for house cleaning as it is built for cats.  Bilbo also can't get
out as you have to raise a long metal bar over the door to open it.  I
highly recommend it and the plastic bottom is on wheels so you can easily
transport it from room to room without having to disassemble it.  BILBO give
it two paws up!!
[Posted in FML issue 2239]