I made my own, they are very much like the ones shown in the Kitplanes ad. It is mostly labor in making them so you can figure out if you should make or buy. One thing to think about is to have the cover plate thickness less than the skin thickness if you will be using a seal under the cover.
Another thing to consider is the skin of a monocoque design is primary structure, I would suggest you do your homework/contact Van's prior to cutting a big hole in the structure of your aircraft to be sure you understand what's involved. Just because someone offers a kit for something that doesn't automatically mean it was tested or approved by the aircraft designer (I'm quite sure Van's did not endorse/approve the installation of the above linked kit on their aircraft).
The advent of large EFIS screens and designing panels that come out as an assembly eliminates the need for access panels.
Build on.
Carl
I would agree with this also. With the way panel equipment is today, I would try to keep everything on the front part of the sub panel. It is a lot easier to sit in the seat and work on the stuff behind the panel. If I was building today I would design everything to be accessible while seating in the seat if possible. I do love my "Affordable (three section) Panel". With the new large holes for screens that helps also.
Pulling the EFIS(s) gets you past the panel, but there is a subpanel ahead of that. Forward access covers get you into that area.
Ed Holyoke
I fully understand that, I have access panels on my plane. If I was building today I would just mount everything so that it could be accessed on the sub panel, it could be accessed via removing the instrument panel. I just could not do that when I had analog gauges. The big brain box for my AFS engine monitor and my Lightspeed Ignition box are mounted under the LH panel. My altitude encoder use to be under the RH panel, no longer needed, now that I'm using the Garmin G3X. I use clear RTV when installing them and they do not leak. I have been back into them a number of times. I made this mod myself, they are not the ones being sold, but are made like them, only smaller. Feel free to go to my web site and look at my ugly plane ;-)
Another thing to consider is the skin of a monocoque design is primary structure, I would suggest you do your homework/contact Van's prior to cutting a big hole in the structure of your aircraft to be sure you understand what's involved. Just because someone offers a kit for something that doesn't automatically mean it was tested or approved by the aircraft designer (I'm quite sure Van's did not endorse/approve the installation of the above linked kit on their aircraft).