Modern Rack Rails in Classic Racks?

I think part of the answer is that I'm going in circles. :-) I have 4 DEC Racks, but all four are full, and since the initial post, I?ve concluded they?re off-limits. I don?t have any RK05?s, and the RL01?s and RL02?s will stay in DEC Racks, as will the majority of the DEC HW. The primary objective is to mount a DL380G7 and a 1GigE switch. I also have some desktops that I?d ideally like in the rack, and maybe a MicroVAX III and PDP-11 or two (those are if I go the route of a real rack). Earlier in this thread, I?d pretty much convinced myself to use a wooden rack that I have several of. Then I remembered why I moved from those to Gorilla Racks. The wooden racks are pretty unstable. I?ve found good deals on a variety of modern racks at a local place. I?m now strongly leaning towards this option. My next question is, what options are there for putting a shelf in a standard rack? My google-fu seems to be failing me. I?ve I?m going to put any desktops in the rack, I?ll need a shelf or two, at a minimum. Zane