Hi LoveBunny,
The closest factory direct manufacturers to you are in Richmond, VA. If you go in that direction they would be well worth a visit. They are listed in post #5 here.
Local outlets that may carry all latex that I know of (and other types of mattresses as well) are …
http://www.mtvernonsleep.com/ Fredericksburg, VA. Retailer that carries Pure Talalay Bliss and Savvy Rest latex mattresses and some Paramount mattresses as well (make sure you can find out the specifics of the materials inside the Paramount mattresses)
http://winndom.com/retailers/ See the retailer list on their site for VA stores. I don’t think they make an all latex mattress but it may be worth calling them to find out for sure and if they do which retail outlet near you carries them. Their mattresses tend to have better quality and value than most national brands and would be well worth considering depending on the knowledge of the retailer that sells them. Their retail outlet finder on their site may not be up to date so a call may be better.
Some of the other better local possibilities that would require some further research to make sure they are willing and able to provide the information about what is in their mattresses and to find out what they have on the floor (and the brands they carry that may be more likely to disclose the materials inside them) include …
http://www.mattressdiscounters.com/ Fredericksburg, Stafford, Woodbridge and others in the area. Classic Brands.
http://www.virginiamattressdirect.com/Default.asp Fredericksburg, VA. Park Place, mLily
http://www.rankinsfurnishings.com/ Warrenton, VA. Winndom
Shop Affordable Home Furnishings & Home Goods - IKEA Woodbridge. See post #3 here for the better possibilities here.
In the other direction in DC … post #2 here has some of the better options (some of which you’ve mentioned or are already listed in this post).
Hope this helps
Phoenix