Cheers dude
The shelves/ttays are actually both retractable so i can have either the controller out or the xl out or both (as shown above) so i can actually do what your suggesting already. The xl and S2 (controller) trays are at full extension in the pics above i only tend to use one at a time, the S2 is used for handling mp3 samples or just having a mix i do have a turntable but havent bothered to set it up as im happy with the S2 (ive been sampling mp3's for years and only do the odd scratch or accapella mix with the turntable and now im in smaller space ive put the turntable away for now but its there should i need it)
The little tower thats just visible in the lower right (with t shirts/dust covers on) of the bottom pick has a cheap board square on topwhich is where i place the laptop its in full view when im seated in front of the main stack of equipment (staiway) so i hot that base covered i did toy with putting it where you said but the spaces either side of the other equipment arent big enough for the mixer and the laptops proximity to the large magnets inside the speakers are a worry to have so close to my laptop ideally another shelf above the speakers would be ideal but its a bit inexcessible if i want to use the keyboard of the laptop
The stairway also sits on 2 breezeblocks which raises the desktop (mpc level) thus raising the trays and allowing me to play the xl while seated i usually stand when im mixing on the S2 (i only use it to record samples amd mix to answer question i havent got any midi cables because i dont want to use any external midi at all when making beats) however when using the S2 for doing less animated activities like sample recording i can also be seated. Also out of shot i have a dj mixer that tethers the inputs (S2 and xl) for sampling, its situated at the base of the stairway so eveything is in arms reach when im sat down this has improved my workflow to no end
Thanks again