I looked at a woods subframe for the BH and it looks really easy to mount up and would provide a decent bit of protection on its own. It would also be very easy to attach a belly pan to directly using u-bolts or some other clamping method. Most of the impacts and snarls that would hit the bellypan should push up or back and not try and pull the belly pan down. All the bulldozer bellypans I have seen were dented upwards.
The BH subframe didn't look too cheap but I didn't get a price. It comes packaged with the part that attaches to the BH so there would be a little waste in purchasing the subframe for just the bellypan frame. It used very substantial steel. Looked like 1/2" plate with gussets.
The pigtail is just asking for brush to rip it out. I ordered one more than 6 months ago and it was "backordered". So then I was placing this most recent order and decided to reorder the pigtail from this more established dealer. Being 4.50$ it was not a big risk and I can only imagine it ripping out again. The dang pigtail arrived in less than a week with the other parts. Maybe backorders expire? Check out the piggy pick, part# is there too.