I was unable to find a Bryson tartan. However, many of us feel that Bryson is a derivative of Bryce. I was able to find a Bryce tartan. It is tartan registration number 1537. It isn't available from all of the tartan shops, but I was able to find at least one source for it at The House of Tartan in Scotland. If you find another source, please let me know.
As an alternative to wearing the Bryce tartan, you can also wear the MacFarlane tartan. The Bryce family was actually a sept of the MacFarlane Clan, even if we had our own tartan(pictured left). For more information on the MacFarlane Clan, see their website.