Some issues I am seeing. If you have 5 singles and 5 doubles as your picture shows. you do not have a good water protection at the seam. Next would be the obvious and that is you maintain 5 nucs side by side that are all within reasonably the same level of development. How reliably are you able to do that. I see a situation that under developed colonies suffer and over developed colonies suffer. do you swap frames around to balance out colonies?
So far my increase methods are focused toward the use of either mini nucs or a queen castle I make that has 4 2 frame compartments per ten frame box. Once the queen is mated and confirmed I move her to a 5 frame nuc and build up to 5 over 5. I like this design as it is consistent with the side by side single unit configuration of the queen castle. the queen castle on steroids.
I will have to do some math comparing material costs for 10 nucs to the cost of this but with the elimination of the bottom boards it is very likely to come out lower cost.
One other concern would be the transferring of nucs to single units for sale or transport to other locations. I have issues with getting bees moved from queen castle compartments. many of them are still running around on the walls of the compartment after the frames have been removed. Time involved to salvage these orphaned bees is a big issue. the alternative is to simply allow them to be lost or migrate to any other populated compartment. Most remain in the empty compartment and eventually perish.
How do you clean the bottoms out?
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.