That Misumi extrusion looks very nice, and I seriously considered it, but instead used the Orange Aluminum T Track mounted on 4 additional 20mm extrusions. See here:
If you are starting from zero however, it isn’t all that much less expensive than the Misumi. 7 36" Tracks is about $65 shipped. You will have at least $60 in 20mm extrusions and corner brackets plus another $20 to $30 in nuts/bolts/etc. Probably close to $175 total cost. I used up the better part of a $100 gift cert from Inventables in this upgrade just getting the substructure. If I wouldn’t have had that, then the Misumi (easiest) or Phil’s wasteboard would have been higher on my investigation list.
–Rick