For harness, western saddles, and mane rolls, flowers, and other equipment definitely check out mydrafthorse.com the Granstaff's are very helpful and nice people.
If you want to ride English I have had lots of luck with the Wintec, Collegiate and Bates lines of saddles that have the easy change gullet system. I get the extra wide white gullet and it has fit all 3 of my clydes. Wintec also makes the Wintec Wide which is way wider than their standard line of saddles and gullets. The thing I love most about this line of saddles is that I can buy a great saddle once and even if in the future I decide not to ride my drafts I can change the gullet so it fits a light (regular) horse. I personally have the wintec 500 all purpose for everyday riding, the wintec 500 dressage, and the Bates Caprilli Eventer for jumping. I love them all have had them for many years now and am very satisfied with the quality, fit, and apparent comfort of my horses. PS it is worth paying the little extra to get the CAIR air panel system. My horse moves noticeable better in it than when in a standard flocked saddle.
I purchase most I my riding tack at our local shop called Big Dee's Tack you can check out the saddles with the easy change gullet system at: Big Dee's Tack & Vet Supplies | Search Results
I also get the Weaver Oversize english bridles Big Dee's Tack & Vet Supplies | Product Information
They also have a black dressage bridle that is nice Big Dee's Tack & Vet Supplies | Product Information
And Draft size western bridles Big Dee's Tack & Vet Supplies | Product Information