I built one and use it quite a bit.
The boxblade works great for backfilling houses.
It works like a small bulldozer.
Also leave the rippers all the way down and use the rollback to rip then roll forward and push or pull the loosened dirt.
I've got a 10.5' boxblade I built to level driveways and it works great, follow behind the dumptruck and level the stone perfect.
I need to build a set of wheels on my 8' rake to run it in forward to finish yards.
I don't have any pics but I took a 3/8" thick plate and put on the angles to mount to SSL, on face side I welded on 1" thick blocks w/ holes to mount a Speeco 3PT Q-T (I can take it off to use on tractor too)and put a 2" square tube on it for moving trailers.
This makes hooking up real easy.
Also have a TSC 3 PT carrier and can use it on either machine, plus can dump it w/ the SSL.