I built this one a couple years ago--after determining that most prebuilt ones were cheap and good ones were out of my price range and either way none had some features I wanted. I have about $400 into it. The 8" casters were expensive, I tried pneumatic 8" tires before, that was a no go. To much weight for them and by the time you got enough pressure in them, they were ready to pop off the rims--plus it rocked--a lot, when you revved the engine.
It is still a work in progress, I modify it as I go along. It is currently set up to run big and small block Mopars, and big and small Chebby's. Also have a bellhousing for a slant six too if it ever arises.
I have been using a Chrysler electronic ignition to fire all the engines run so far--I made an adapter to hook it to MSD distributors. I don't bother with the mechanical fan anymore, I also have a blue pump and regulator to run engines set up for electric pumps. Mechanical pump engines I run through that pump to verify all is operational. I run a volt gauge, oil gauge and temp gauge. My timing light has a tach function on it.
A 1.5-2 gallon fuel supply has been more than adequate for engine break in so far, I have just recently got a dedicated gas tank that I need to mount up somewhere. As far as where to mount the batter, wherever you can find room to do so. I still have to make a bracket/box, but want it not permanetly mounted to the stand.
The exhaust is a couple of 2.5" swapmeet "turbo" mufflers. I have about two feet of straight pipe after them. I use various adapters I made for manifolds that go to 2.5" or just use 2.5" collectors on headers, and I have two 4 foot sections of flex pipe to connect to the mufflers. I just set the mufflers on jack stands.
I also made it high enough to be A)comfortable to work on, and B) if you ever had to drop the pan, you could while it was still on the stand. I also made it so the bellhousing support unbolts and you lay it down and rebolt it on so it is flush on the frame and the radiator yoke also unbolts.
This is by far one of the best investments I have made and has saved my bacon twice before engines got put into cars. One leaked water from a side head freeze plug, the other had a oil leak that was hard to spot from a valve cover in the rear.