Sounds like the later models were more practical in design. I did buy two "portholes" that I was going to install in the original fiberglass cover for accessing the
propane bottles without having to remove the entire cover - I saw that here on the forum and it seemed like a great idea (accessing the batteries is relatively infrequent, but accessing the propane is not infrequent at all). However, I decided to do two 6 volt batteries instead of one 12 volt, so I had to change the cover anyway, because the original would not have fit that configuration.
I originally wanted to buy an off-the-shelf diamond-plated aluminum tongue box (most decently-built were about $450), but I ended up having to pay $1,000 to have one custom-built because none of the off-the-shelf models could accommodate the combination of the Bigfoot's front wall being angled out and the front
light over the tongue. The original fiberglass cover, if modified with portholes to access the propane, is definitely going to fit better than anything I could find off-the-shelf and would be much less expensive than getting custom-made (unless you happen to be a welder who can build it yourself). Cheers!