Future candidates for top-paying supergrade federal jobs would have to transfer more, undergo intensive career grooming as well as face wider and tougher competition under an executive-builder program being studied by the White House.

The report of a blue-ribbon task force on executive development has been delivered to Civil Service Commission Chairman Alan K. Campbell. Campbell set up the group, under Office of Management and Budget's Edward F. Preston, to figure out new and better ways to pick the government's elite ($44,756 to $47,500) corps of top bosses. If Campbell and President Carter buy the recommendations, it will mean major changes in the way middle managers in government are prepped for top jobs, and could increase the flow of outsiders into Grade 16, 17 and 18 jobs.

Proposals in the report call for a variety of field and Washington assignments for supergrade hopefuls, and intensive job cross-training. It would require agencies to develop lists of hopefuls for supergrade jobs in the future, and encourage occupational changes for mid-managers in the pool awaiting knighthood to supergrade status.

The plan is modeled after the Internal Revenue Service's executive development program, considered one of the best in government or industry. Graduates of the program would go into the new Senior Executive Service. It would gradually replace the more tenured structure Uncle Sam now uses to house top career executives. The SES - part of the civil service reform package - eventually would take in all 9,200 top career and political appointees in the top levels of government.

Recommendations in the task force proposal place heavy emphasis on early identification of possible executive talent. It criticizes the present program in which many agencies make relatively quick picks of top executives, usually from a small group, in agencies where vacancies occur.

The new system would allow agencies to run their own executive development programs, but require them to meet certain guidelines so that executives could be traded around and moved from department to department more often than at present. Agencies that persisted in offering candidates with "narrow" career development or lack of field and headquarters experience would have a harder time getting their Grade 15 personnel cleared for bigger and better jobs.