I finally finished a project!
I've had the material to build this filament rack for quite some time and finally set aside the time to put it together. I used the BROR cart from IKEA as the base and added a rack made from 1515 extruded aluminum bars from 8020.com to hold the filament up top. The 1515 profile is probably a little overkill strength-wise for this job but it was sold as surplus on ebay so it was almost reasonable, it came already painted black so it matched the cart, and it looks very similar to the extrusions on the printer itself. I used Baltic Birch plywood for a shelf on top and also for a mount on the back to attach the buffer vertically. I printed a dozen retainers in Prusa orange PETG to hold three Sterilite gasketed containers in place on the shelf so they stay put. A pair of the stock Prusa spool holders fit in each of the Sterilite containers, I just drilled a hole through the bottom and attached some printed flanges for pass through Festo fittings and Capricorn tubes down to the buffer. Ran a short test print for all five slots and it completed the 100 changes with no interventions. Really happy so far with this MMU, only time I had to assist a print was when I ran some brittle PLA through it that snapped in the buffer. It alerted me so I was able to rethread the filament and it continued along to completion. I had left the roll sitting out for too long, flexed in the buffer. I usually store all my filament in 2 gal Ziploc bags with desiccant in a larger gasketed tote but I got lazy I guess. Hoping I can leave five colors loaded all the time with these containers, I'll just retract the excess filament in the buffer so it's not bent under tension when it's not in use. Running a stock setup otherwise, with just a silicone sock added so the fan wouldn't cool off the hot end when it kicked on. Most of what I print are badges and nameplates and it works great for me. I need to work on a print profile for my .25 nozzle next. Some of what I print would sure benefit from the smaller nozzle. Not sure why Prusa didn't release an official profile. I've seen other writeups for it so I know it works.
Happy Printing!
Stephen