Ahh, geez, oh how one can waste away the hours messing with Macs!
:d
A Gossamer LB fits nicely in a IIcx box:
http://mywebpages.comcast.net/macdan/images/g3cx/g3cx_lh.jpg
Slot-load combo drive from a TiBook. :d
several more pics:
http://mywebpages.comcast.net/macdan/images/g3cx/g3cx_rh.jpg
http://mywebpages.comcast.net/macdan/images/g3cx/g3cx_front.jpg
http://mywebpages.comcast.net/macdan/images/g3cx/g3cx_inside.jpg
How about a B 'n' W LB? A tad large, but could be made to fit:
http://mywebpages.comcast.net/macdan/images/g3cx/g3_bnw_cx_.front.jpg
http://mywebpages.comcast.net/macdan/images/g3cx/g3_bnw_cx_rear.jpg
I tried a Quicksilver LB but it's too big. 
Dan K
PCI and NuBus Slots are different spacing apart. you wont be able to use cards.
-- just hack up the rear of the case. You have to cut it up near the bottom for Gossamer's ports anyway. And you may have to do some rear hacking for the different PSU (AC jacks) as well.
And he'll be cutting up the case if he wants to make the slot loading optical drive functional too.
Matt
http://www.68kmla.net/viewtopic.php?t=630
just a little info.
kyle