I'm not sure Sunline ever had any 14" tire covers, only 15". Prior to the silkscreened logo covers that started around 2000 (which was around the time they standardized to 15"...within a couple years), they simply took a plain white cover and stuck a vinyl trailer decal on it. So if you can have a decal from your trailer replicated, get a decal made, then stick it on the new cover.
The vinyl decal will probably crack in time, but the covers don't last a long time when exposed to the elements anyway. You can have a custom cover made, but it'll probably be more expensive than having a decal made to stick on.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR