From my experience, both as a retailer and a producer, distributors don't want to deal with solo vids because they just don't move as well as hardcore......unless it is in a niche market where the market is not flooded with content. Even with that exception, you are not likely to move huge numbers. If you kept your production costs low (i.e. re-using solo content from paysite shootings) and produce it on DVD's, you have already expensed the cost of the models to your paysite, and then if you burn it on an "as needed" basis, you could generate a little extra profit from your content.
on our wehovideo website, solo is one of the worst performing sales categories.

But overall, the answer for me is no. not worth it as a major product line.