I have both a Hobart 140 and a miller plasma cutter on my HF cart. The welder faces forward and the plasma sideways behind it. I used a couple 2x4's on edge to raise the welder so I can easily access the flip up door. I welded a half moon shaped pan on back with a bracket that bolts to the lower shelf for the bottle to sit in and used the "u" plate and chain from the welding machines original bottle holder on the middle crossmember so I can use short/tall bottles. I left the wheels as they are. All of my welding c clamps hang on the handle and my electric grinders hang on center crossmember below. Drawers contain welding supplies, welding vise grips, grinding discs, flap wheels etc.
Pros:
Everything in one place, cutting, welding.
Easily reversed with only a few bolt holes left in cart so it's not permanently damaged.
Provides a flat top to act as work bench.
Both machines and grinders are all 120 so one heavy extension cord and I can work anywhere around the shop and outside.
Cons:
The plasma whip protrudes from the side 4-6" so I have to be careful not to drag it into doorways, walls etc.
I never need anything from a drawer until I have something heavy on the top and can't open them.
OR I leave the drawers open just a tad so that when I am working with something on the top I can access the drawers but when I roll the cart they fly open catching a doorway, wall or whatever...
The cart is ****** HEAVY now, totally exceeding the rated max, my fault.
c clamps cover the entire handle making it hard to navigate with all that weight and nowhere to grab. I could probably make another clamp bar to hang them on the rear but haven't got around to it as I'm still deciding if I want to make a dedicated vertical cart with machines stacked.
So if your young, have good eyesite why not? Otherwise I'd sacrifice the top lid and have the welder more accessible. On top.
