Usually what you want to do is get in to one of the pre-sales teams so you are part of the sales process but can still stay technical. This will let you see the sales process and start developing new skills. This is usually focused on the enterprise market where the pricing justifies a more expensive sales process.
You can also do this at a startup but it won't teach you sales typically. Startups are learning how to sell themselves usually, so they don't have a mature sales process or people so if you are wanting to develop those skills go to one of the big consulting firms, or CRM companies etc.
As far as I can tell, many things are limited only by the amount of complexity people are willing to handle and the workload they can support. If you're okay pulling a work-day with co-workers and then another one when they leave, then we understand each other. Some people can pull off 16 hour work days or more, even during the week-ends, even during holidays and think about the product all the time. Some are great and can do that in 4 hours, I personally can't.
Find things that suck, fix them, institutionalize that knowledge, document everything, prepare for the eventuality of your disappearing, build an organization, train people to think like that, read a whole lot, become good a things, add a lot of value, become someone you would fear if they were a competitor, have very high expectations of yourself and be afraid to disappoint yourself tomorrow, experiment, demonstrate by building things and implementing things, not just as "ideas" but actual outputs, either codes/graphics/copy/documentation/training manuals/videos. Go for it.
*Yes, I looked you up. I'm that good.
Promise not a stalker!