Great clean job Bob! How did you attach the aluminum sheets? Where they screwed into supporting joists on the left/right sides? What type of screws did you use? Looks like allen nuts. Did the aluminum come in black or did you have to paint them? What did you use to cut the sheets?
Re: How did you attach the aluminum sheets, I trimmed the edges of the rough opening with 2X2's and screwed the plates on top.
Re: What type of screws did you use, I used some Torx head screws I found at Lowes and some finishing washers
Re: Did the aluminum come in black or did you have to paint them, I painted them. Used Mar-Hyde (black satin automotive trim coating)
Re: What did you use to cut the sheets, used a jigsaw with a metal cutting blade. Then filed the cuts to finish them off.
FYI - Got the idea from this thread on AVS DIY A/V rack
Hope that helps, any other questions just let me know.