Ideas to improve existing products or even new ideas for complimentary products should be seen as part of your job. While many companies are not open to tech employees bringing new product ideas to the table, many are.
This sort of question only ever seems to come from technical employees, who tend not to interact with customers much. Sales guys -- the good ones at least -- come up with new ideas all the time, and see that as part of their job. You should too.
If you want part of the profits from your ideas, then you need to start your own business and develop those ideas yourself, outside the security of a 9-5 pay check.
