Here are examples of two highlighted possible career paths for someone with your skills.
The first one involves creating small business software that simplifies compliance of government over-regulation in some industries, such as home construction. Simply pulling a permit can involve over 30 forms involving local, state, and federal governments. Much of the information on these forms are redundant, require various calculations to be performed, and can benefit from a compliance checklist.
Many small business owners hate dealing with the "mindlessness" of dealing with these excessive regulations. A decent software product would save them time, aggravation, and possibly money through less chance of fines being levied for non-compliance.
One of the keys here is to research the industry and talk to business owners and employees to find out what issues they face and what they need to simplify their lives.
Annual pricing for this software product could be based on estimated hours saved times an hourly rate, say $20.00 per hour times number of permits typically pulled per year, say 12. An annual subscription would be appropiate as you would need to keep up with continual regulatory developments.
The other key would be marketing. In the building permit software example given, one might considering focusing in an active building state with heavy regulations such as Florida or California a a start.
The second idea involves corporate consulting. Many large companies, say fortune 1000 size, have significant productivity issues based on outdated management training, ineffective inter-departmental communication, and inefficient risk management strategies.
I see an effective corporate consultant as having broad-based business knowledge, an effective problem solving methodology, exceptional research skills, strong visualization skills, and excellent communication ability with a wide variety of personalities. And no, you don't have to be beyond CEO level on all these. Grin.
A lot of information about the issues a prospective company faces can be seen in their annual report and on their website. Follow up inquiries can be made with employees for the creation of a proposal for management.
I would focus on companies that are not performing well as compared to their competitors. For companies that have an CEO that has an accounting background, it is not unlikely he has broken the business model of a previously successful company.
Additional keys here are to understand the CEO's personality type and to explore gaining management level authority over certain issues.
Pricing your services would consider the realizeable productivity gain of employees and the monetary value of specific problems solved. Using a return(The recurring productivity gained) on investment(the money you are paid) of 100% in a year typically yields a price of $400.00 per employee per 1% of realizable productivity gained. This formula yields huge consulting fees that management will balk at paying, but this is where preparation, marketing, and negotiation comes in.
Your energy level of 25%, when focused, is probably more than double the input of average managers. To up your own energy levels further, find a way to safely excerise vigorously. Absent a serious medical condition, you may be able to obtain up to 70% of the energy level you had in your prime until your eighties.
Consider teaming up with some of your former competent co-workers. Best wishes to you and good luck.