I was a developer for 17 years and switched into enterprise sales a couple of years ago (with a short stint as a technical account manager in between). The upside of the transition is that sales is still a job for problem-solvers, although you'll be much less hands on. The downside is that there are expectations for performance that come along with the upsides of being paid based on that performance. I still hack on stuff in my spare time, but that time seems much less abundant now (certainly less time to surf HN, for example ;)).

If this is something you're interested in, many organizations are in need of sales engineers (pre-sales technical folks) who have real experience from the trenches. If you are comfortable talking with technical and non-technical people alike, sales engineering is probably the best place to start. The challenge with getting into a purely sales role is that many places expect a level of experience before hiring people. Negotiations and proposal building can be surprisingly complex, and there aren't many organizations interested in training-up sales people. Sales engineering would serve the purpose of giving you exposure to the pre-negotiation piece of the sales process, as well as introducing you to a lot of people with deep experience in the negotiation / closing process.

I'd be happy to chat with you offline about my experiences as well -- my email is in my profile.