Molly if you have a compressor hump in there, i would imagine you would get two corny's in there, + additional corny's on the hump if you built a suitable collar.
I have a 210L chesty, i can fit 3 in left of the hump and i reckon the 2.6kg gas bottle as well (but i have a double reg so it wont fit there without some creative problem solving).
With a collar I would be able to fit 2 more corny's on the hump if desperate, but i would probably use this area to store hops etc and keep em out of the Mrs's main fridge.
I would build the collar, especially if it is a new freezer, that way if it carks it during warranty, you can go get a replacement after restoring it to 'as new' condition.
Cheers,
D80