Sorry, but you won't get the same quality in that size, that's the short answer.
The long answer is that we did have them in 60cm octa, and also in a small rectangular version, but when we went to re-order them we found that the manufacturer of the mechanism has now discontinued them because, in that size, the manufacturing tolerance of the cover is absolutely critical - too slack and it flops around everywhere, too tight and it creates too much stress on the mechanism.
As from next month we will have something very similar but in 70cm octa, and it will only fit flashguns, not studio flash heads.