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. If I wasn't so time constrained these days I probably wouldn't even be batting an eye about knocking out the work though. Ah well.
Carry on!
P.S. Jealous you can weld aluminum, that would open up some more possibilities on things as well.