Hi paddybiagi,
Welcome to the Mattress Forum! 
Unfortunately, there aren’t any manufacturing members here of the site in the Minneapolis region.
I have discontinued the provision of listings of potential retailers in various geographic regions (unless they are already approved site members), because of the difficulty in maintaining such lists in a retail landscape that is constantly changing, and most importantly the confusion it was creating with the consumer members who incorrectly assumed that these businesses had indeed gone through the strict vetting and qualification process and were approved as members of The Mattress Underground. Such an assumption is unfair to both the consumers seeking assistance, as well as the very businesses and manufacturers who have indeed qualified the be members here of The Mattress Underground.
You can perform a forum search on Minneapolis or any other area and see what other businesses have been discussed in that region which may be helpful to you.
Aside from that, I would always confirm that any retailer or manufacturer that you wish to visit is completely transparent (see this article) and also make sure that any mattress that you are considering meets the quality/value guidelines here.
If you have any questions about specifications or certain products that you discover, feel free to post back on the forum and I’ll do my best to provide answers.
Phoenix