The style of cell utilised by Kriege & Barry uses a sling to hold the mirror in place. Your question got me to thinking that this may not be the solution you need. Have a look at the cell photo on this link, it uses a more conventional 'clamp' to hold the mirror in place:
http://home.freeuk.com/m.gavin/bigdob.htm
It too is low profile & made of al. Maybe all I would change here is the configuration of the cell's frame to the triangular cast one of the first link.
Only other suggestion is to surf around for info on other cells and adapt. I'm building my own dob, so the sling solution is what I'm using, but it is not eq mounted. One I found is here:
http://www.oneilphoto.on.ca/oneilatm.htm
Mental.