I've heard that the welds are weak on the ones from Northern tool, don't know from experience. I just built my own skid, the steel cost less than $200, and my brother (a millwright) welded it up for a half rack.
I would recommend that you use a "real" Honda motor, the el-cheapo copies on eBay just don't hold up, this much I do know. Also Hannay makes a hose reel that is far superior to Reelcraft. I have no Idea about Coxreels as I have never used one. I prefer Hypro diaphragm pumps, though I also have an Udor Kappa 40 that works just fine. As far as tanks, it is my understanding that the horizontal round ones are the best for agitation.
tell that to that man's poor pathetic fat kid!