Have you got am idea on what the final product will be? What "mobile" platform did you decide on? Looking forward to this! Your last upgrades to your other splitter were great! I can only imagine this will be the same!!
I'm planning to start with a basic horizontal splitter... Nothing too exciting -- 28gpm, 30" stroke 5.5" bore. Adjustable 4 way or maybe a box wedge. The main beam is going to be 6x8x1/2" tubing with 1x8" plate welded on top for the push block to ride on. I'm torn on an auto cycle valve or not; might just go with a double detent this time. I'm not planning to haul it on roads so I'm going to make some sort of 4 wheel hay wagon type of running gear with a telescoping quick hitch. That way I should be able to tow it with a garden tractor since there won't be any weight on the tongue. I'm going to use highway rated tires just in case I want bring it somewhere some day. Once I get that done the fun part will begin IF I can find a light weight mechanics crane from a service truck... I want to build a hydraulic mini log loader with a grapple to load the splitter. It doesn't seem all too hard to make one except for the rotating base of the crane. I have some ideas but finding an old hoist would make life a lot easier.
How about using a hub from an old trailer axle for the rotating base? Something with some nice roller bearings.
Here's a link to the truck crane I started with Mike, to make my log crane. Can't build the lower section for what it costs. And, I'm going to use the hand crank winch on a tripod this winter, to lift logs up so I can get them on skis. http://www.northerntool.com/shop/tools/product_74569_74569
Check this out Mike to start the base of your crane with. Can't build it for the $. http://www.northerntool.com/shop/tools/product_74569_74569
I'm hoping to find something like this to build off of -- my tree guy could dump rounds right next to the splitter and I'd never have to get off my azz to split it all. I'm not sure those half ton truck hoists would be strong enough for the 8-9' reach I want. But I might end up copying the basic idea for the base with round stock in a pipe. It will be a while before I build a loader. I need to build the splitter and get a years worth of wood split first so I don't fall behind.
I think you'd be pushing this crane I showed, and used myself... with logs. I have a 10' section of 2"x2" slid into the lower section instead of the short boom that came with it. Lifting a 200 lb round is OK but 300 lbs might be too much. Yup, if you're gonna go for logs, you're gonna need some beef. Don't wanna see a post here with the results of a crane failure. I tried to find the little tiny 12 volt elec grapple I saw about a year ago on YouTube. It was pretty simple and could be used as inspiration to build your own grapple. I want to build one too for picking up rocks. I have a lot of stone walls that need work, and I'd have to do it mechanically and not with my back. If I find it, I'll get you the info.
Mike I don't know if this would work for what you are wanting to do but I used the front wheel bearing assembly from my 03 dodge 3/4 ton truck. You can see in pic's the rotor I used for base of the boom. I use a piece of rope for the swinger. I believe this will be a lot cheaper than a boom off of a service truck, just not near as cool though.
Looks like you are lifting some pretty good weight... I wasn't sure the bearings would take such a load. Any close up pics?