An obvious way to transition from engineering to sales is via the "sales engineering" role at enterprise software companies, which, for complicated products, is the tech guy who tag-teams with the account manager and does the product pitching. SE pays about 80% of what high-end dev pays (and nothing resembling what sales account management can pay) and comes with virtually no execution risk.
The downside of SE is that it's a tar pit --- you'll never transition from SE to sales in the same company --- and after doing it for a few months you'll quickly learn an important but disheartening lesson: that a rock-solid technical pitch and a rapport with your target market is only 10% of the sales execution mix, and the other 90% is black magic --- a good chunk of which involves being shameless and irritating.
Then again, being shameless and irritating may be part of What It Takes to make a startup break through.