While I'm all for bodging and building, it'll be cheaper and easier to buy a BH than make one ! Unless you've got a FULL metal fab shop, a COMPLETE hydraulics shop and , well, a LOT of time on your hands.
I'm a little late to this party, but I beg to differ. I
built my own FEL in my garage off and on in my spare time in about 3 weeks (I did spend a month or two before that researching, measuring and
designing in CAD). Materials cost was less than 1/2 the cost of purchasing an aftermarket FEL (OEM Kubota FEL is made of unobtanium).
I do have a home machine shop, but the only things I made on the mill and lathe
were the hydraulic block, pins and my fancy SSQA mechanisms. Everything else could be done with as little equipment as a hand grinder with cut-off wheel, power drill with hole saw (or drill press or even torches) and a welder, although a band saw or chop saw would be handy.
I have a plasma cutter, but many metal suppliers will cut your order of sheet metal for the bucket to size or you could go the cut-off wheel route. 1" DOM tube is perfect for the pivot bushings and nicely fits 1" bar stock for pins. I drilled the grease passages in the pins in the lathe and mill, but a drill press would also work. Failing that, it's even possible it could be done with a hand-held drill and a vise. The style SSQA mounts I built are not neccessary for most applications, a traditional lever style would be fine and that could be made with the above tools or purchased as a unit.
I bought the hydraulic cylinders at Princess Auto. Same with the hoses and fittings, although I bought the joystick FEL on eBay since PA didn't have one with the features I wanted.
If I hadn't stumbled upon a great deal on a Kubota BH, I might have made my own one of those too. A little more complicated, with higher materials cost due to the additional hydraulics but I had done some preliminary sketches and am sure a BH could be made with the same tools and skills. You can even buy
pre-engineered plans online (I have no affiliation with that vendor, it's just an example).
Now, my advice to the OP is get the backhoe first, build the subframe to match. Unlike SSQA, there is no standard for BH dimensions, they vary wildly between makes and models.