2Rabbits (Newbie),
First, it would be helpful to members to know where you are located, especially when asking for help. What is advised might depend on where you are, so why not add this to your profile.
I suppose that OEM mirrors are likely pricy, so you want aftermarket suggestions. First, I suggest using the site "search" function (at page top) to see what has been posted in the past for Trophy mirrors.
Secondly, periodically check out Ebay.com. Currently there is a right side OEM listed. Still pricy, I think, and only one side, but here is the listing:
http://www.bikebandit.com/emgo-oem-r...=1032&t=1&td=1
Thirdly, I suggest trying some of the motorcycle parts sites. You may have difficulty finding compatible morrors, but a telephone call to a place like Bike Bandit may yeild results. Knowing the thread size and pattern of the OEM might help to get a match. For example, these Honda mirrors look acceptable, and maybe Bike Bandit can help determine if they would fit. It is a free call if you are in the U.S.
http://cgi.ebay.com/ebaymotors/Right...Q5fAccessories
Lastly, check with your Triumph dealer. Mirrors from another model may fit your Trophy and thereby expand possibilities. I recall from a post here that the Sprint mirrors from particular years will fit my D12. Maybe you will discover a similar compatibility.
Good luck. Sorry I do not have a definate match, but maybe someone else will have a sugggestion.