Nice! If I had my tape measure with me I'd go out right now and measure which one of the two bags (11 cu.ft. = 40" x 36.5" x 17" or 15 cu.ft. = 48" x 38" x 18") fits on top of the 1st Gen (and it's probably fairly similar for the 2nd Gen).
One of the two should be a pretty good fit I think.
Dang, the interior width of my dephep rack is 31", maybe could push in 32" or 33" because it's a soft case, but 36.5" would be too wide. Hmmm, I guess I'm gonna ask them to see if they do custom ones!