Interesting, it seems thought that if I try just fitting 2 3.5 inch drives mounted horizontally into the optical bay, they just barely fit, with no possible way of plugging them in...I guess that caddy system is basically the current one with the bottom half cut off for access to the plugs. Thanks for the link, but I think one drive is the route I'll take due to the steep price increase of adding 2 ($139 + (2)cost of drive) instead of the price of just one drive considering i have some 5.25 to 3.5 mounts lying around.
Thanks!