Hi lamont,
Welcome to the Mattress Forum! 
Regarding the company you were investigating, Absolute Comfort is part of the same group of companies as AbsoluteSleep.com, Ahhmemoryfoam.com, airbeddiscounters.com and usmemoryfoam.com
A forum search on absolutecomfort (you can just click this) will bring up more information and feedback about them. I would question the accuracy of their Dunlop ILD’s if the density is accurate (see post #2 here for some rough density and ILD comparisons for 100% natural Dunlop) and in the past there has been some question to the accuracy of their information about their Talalay latex, although the information on their web site seems to be better now.
I’m not sure why you were given such different shipping information (wow), as I completed an order online for them (short of entering the credit card information) and the shipping was built-in to the price of the mattress with no extra fees, although the White Glove special that you mentioned was not an option in ordering (I do see it is still prominently displayed on their website). Combined with the inconsistencies you’ve experienced, I can’t object to your gut feeling to move on.
You are correct that the Therapedic MediCoil HD line is not meant to be paired with a power foundation, and while the specifications can vary between licensees, there usually isn’t a border rod use with the innerspring unit and the common reason for not being adjustable friendly is that the helical lacing of the spring unit runs head to toe and the edge foam encasement is not cut to allow it to bend. But you may have an item that does contain a border rod, and of course this would also preclude adjustable bed use.
For products more appropriate for your BMI, I would begin by reading post #3 here has quite a bit more information and suggestions about heavier weights that is worth reading. I don’t keep a particular listing for mattresses marketed toward higher BMI individuals, as many of them contain componentry that I don’t recommend for individuals with a higher BMI, and it’s more appropriate to focus on the componentry within the mattress, which can make it both a durable product for higher BMIs, as well as other individuals.
A high BMI presents special challenges and generally requires firmer materials (in the support layers especially). This could be firmer latex or innersprings (the type of support component would be a personal preference and in the right design either could be suitable) or even a zoned construction. The same overall guidelines apply with higher weights though that PPP (Posture and alignment, Pressure relief, and Personal preferences) along with using high quality durable materials that will maintain their feel and performance for longer periods of time are the way to make the best choices. Heavier people in general will need firmer and thicker comfort layers and firmer support layers than those who are lighter and because no materials will last as long with much higher weights the quality and durability of the materials and components is even more important than normal. I wouldn’t “rule out” any types of mattress and base your choices on your own personal testing.
A good place to start would be the site membership here, and many of these manufacturers offer latex items and are experienced with the components and arrangements that tend to work well with higher BMI individuals. Looking for online options, at a quick glance Arizona Premium Mattress Co, Cozy Pure, Dormio, Flexus, FloBeds, FoamSweetFoam, Latex Mattress Factory, Luma Sleep, My Green Mattress, Nest Bedding, Rocky Mountain Mattress, Sleep EZ, Sleep on Latex, Sleeping Organic, Soaring Heart, and Spindle offer latex products that may suit your needs. At least that’s a good list to begin your search, and after perusing their web sites a follow-up phone call would be your next course of action to any business in which you had an interest.
Phoenix