Whats about making the Controlblock the only thing which accepts and outputs EU? (like a normal Storageblock but with external upgrades)
This way you can place ONLY ONE Controlblock to every LESU-Building to prevent usage as Cable, and LESUnits CANNOT be placed adjacently between TWO diffrent LESU-Buildings to prevent connecting two LESU-Buildings together.
If its coded properly then it's extreme efficient and doesnt lags at all (even less than a MFSU-Chain!)
Codeexplaining Part:
First you need to place the Controlblock OR a few LESU-Blocks
If a LESU-Block is tryed to be placed adjacent to another one, then it scans all other adjacent LESU-blocks (and their adjacent counterparts), until it finds ONE Controlblock or NO Controlblock (TWO or more, are forbidden and the placement of the LESU-Block will be prevented in the first place), if the Controlblock was found, then it updates (count+1) the Number of LESU-units in the Controlblock, else it just does nothing and just gets placed.
If a Controlblock is tryed to be placed adjacent to a LESUnit, then it scans all other LESU-Blocks, to determine the count and to check, if theres already a Controlblock, if so then it refuses to be placed, otherwise you have just succesfully placed the Controlblock
If a LESUnit gets destroyed (Stevepunch/Wrench/TNT/Creeper etc.), then it will update the Controlblock to redetermine the amount of LESU one tick after it was destroyed.
Edit: Oh i forgot to say +1.