well, in theory, you can stack up "nicely":
31 samples of 65534 bytes => 2.031.554 bytes
64 patterns => 65536
-> 2.097.090
Now, I don't think all Protracker version handle more than 64kb sized samples. I know some do, however, so, that doubles the pure sample size. Also, some protracker handle more than 64 individual patterns. In these cases, the absolute total is :
31 sample 131070 bytes => 4.063.170 bytes
128 patterns => 131072
header => 1084
-> 4.195.326 bytes
that's big

Oh, and we are not talking about the IFF-like version of mods, here ...
Sylvain