It depends what you are willing to pay. There are pairs of captains seats on the web, various sources, but they tend to be expensive, by my measure anyway. Driver's captain seats are cheaper than passenger ones. Most people are looking for the latter because they are changing from double to single, far fewer go the other way. Demand pricing.
You may be able to retrofit armrests to your existing driver seat. Not exactly cheap, but probably less than getting a full seat with armrests. Foams can be changed if worn/damaged. For a T6, you can get a seat from a T5 or 5.1 as well, not just 6 or 6.1. I understand that the foams of a T6 can be fitted to earlier T5 seats to make them look the same. There are other cosmetic differences but if you are having them retrimmed or fitting covers they may not matter.
Seats from cars can be made to fit, but may have lower trim missing because they were not built to sit exposed on the T6 seat base. Not the end of the world though.
Good luck!