I have only built a handful of log splitters from scratch, but have determined a few factors that can not be compromised. I have modified or powered up many. A well built splitter can last 20 years with no problem. With a 100 to 200 cords per year. I do not like or condone guillotine designs as they are too hard on ones back, but for wood more than 4' or 5' they have their place. I worked on a crew that processed 50 or more cords a day and they had one just for large rounds, but used mostly cradle splitters for the rest. They had conveyor belts to load the dump trucks, but no wood processer in sight. I have wood in the back of my dump truck or pick up at the same level as the splitter so as not to have to bend over much. My design uses two horizontal 6'' x .25'' wall tubes with a 1/2'' x 6'' x 6.5' bar welded to the top. The tubes are the oil reservoir tanks which because of the large amount of exposed face is adequate for cooling. A 22HP or 24HP vertical or horizontal does not matter much. A lawn mower motor can be purchased for well under a grand. A twin V cylinder design is quite necessary as they can run 3,000 to 3,500 rpm all day ever day, but not a single cylinder. A 8 gpm 28 gpm two stage hydro pump is essential. I have also used a single stage pump and found over all they are too slow, because they can not handle really heavy knotted wood. A 5" or 6" x 28" to 32" cylinder can be found reasonably if you look around. If you need a log lifter that can always be bolted on or off as needed then plan on it. I have never under stood the concept of multi angled splitting wedges because here in California they will not work, but that does not mean in other states and countries that they would not work well. Depending on the terrain as if you need suspension or not. My current one has 12'' wheels for on the job site needs and large 15'' wheels and tires for transporting on the freeways. If some body maybe could build one for $3500 that would be a bargain, but I think realistically it would run you $5000. Thanks