there's something to be said for buying RV doors, it's way easier than making your own!!
I would think that getting some panels made would be fairly easy no? Have you heard of anyone trying and being denied?? I haven't talked to the people I got mine from , but I would think they could accommodate a purchaser, I do recommend this product, its just pricey. But I guess you are understanding that with the amount of work to build yours up verses buying, like me, some things are hard to justify the cost for if I can make it, it just shows where the cost is once a guy spends lots of hours and money making something from scratch.
Don't worry, I'm an idiot and I'm still thinking about building my entry door.
At the time I was looking folks were saying the rhinocore was being unresponsive to getting quotes out to the little guys, plus I didn't know if they'd do thinner skins (1/8" over the strong core is definite overkill) because the stock panel weight was a bit high for my desires. Plascore didn't follow up with me on pricing. I had heard nidacore was quite expensive. My brief chat with superhoneycomb was rough (it was like talking to a car dealer, being asked what I wanted to pay rather than telling me how much a panel cost) and I gathered they were just laminating FRP sheets (like at homedepot) to their foam/wood core which if I wanted that I'd just do it myself, I don't want that since it's not the strength/weight ratio I'm going for. On that note if I would just laminate typical polyester resin commercial sheets onto my foam cores it would save time as well. But won't nearly have the same strength/weight ratio as the fiberglass cloth/epoxy resin layups that I'm doing. But maybe trading off some weight for time wouldn't have been such a bad idea.
Carry on!
P.S. Jealous you can weld aluminum, that would open up some more possibilities on things as well.