(FORTUNE Magazine) – Rebecca Matthias Matthias, 32, is popular among the growing number of women executives practicing their own versions of just-in-time delivery. She is founder and & president of Mothers Work, a Philadelphia company that has become one of the biggest manufacturers and retailers of maternity business suits. A former construction engineer with degrees in architecture and engineering from MIT and Columbia, Matthias got into the rag trade when she became pregnant for the first time and couldn't find a suit. A major selling point of her three-piece outfits is an adjustable skirt that can be worn as part of a standard suit after the blessed event. Matthias, who has 25 stores, expects company revenues to double to $3 million this year as she diversifies into sportswear. Roger Covey If you plan to automate a factory, Covey wants your business. The head of System Software Associates in Chicago, he designs computer programs that help managers control production and inventories as well as handle accounts and other day-to-day affairs. His package has an average price tag of $50,000 and runs on minicomputers made by IBM, which also happens to be Covey's main competitor in factory automation software. Instead of selling directly to users, System Software has a worldwide network of local affiliates that install and service the program. Covey, 31, says his four-year-old company will double sales and pretax earnings this year, to $20 million and $4 million, respectively. Ted Bernstein Bernstein, 26, has taken a leaf from discount stockbroker Charles Schwab's book and tried it on the insurance industry. President of Assured Enterprises of Skokie, Illinois, he markets no-load life insurance, whose premiums are free from the usual built-in allowances for sales commissions and such broker incentives as plane trips to warm islands. Bernstein charges clients a fee pegged to the difference between his premiums and the industry average; he says he usually saves buyers 15% to 35% a year. The insurance companies that set the special rates for Assured are glad to cut their front-end costs, while Bernstein expects that his lower prices will give him greater volume. He sold nearly $50 million of policies last year, his first, and expects to double sales in 1986. Some insurance traditionalists are skeptical. ''My father's been in the business for 21 years,'' says Bernstein, ''and he thinks I'm nuts.'' Siegfried S. Hecker As the new director of Los Alamos National Laboratory, Hecker's main preoccupation will be the bomb and how to live with it. The oldest nuclear weapons lab in the country, Los Alamos does research on Star Wars and on the technology needed to verify compliance with arms control treaties. The lab, which has a budget of $800 million this year, also delves into matters ranging from artificial intelligence to synthetic veins. A native of Austria, Hecker, 42, joined Los Alamos in 1973 to do plutonium research. ''Plutonium has a bad reputation,'' he says, ''but it is the most fascinating and complex of elements. You can learn a little about almost every other element from it.'' Earle F. Moloney Moloney, 39, has a penchant for sawing cars in half, and he is not reenacting a scene from a Grade B movie. The not-so-wanton destruction is the first step in making a stretch limousine, of which Moloney Manufacturing Corp. of Chicago is one of the largest U.S. producers. Moloney begins with a factory-built car, usually a Cadillac. After chopping it in two, he adds a couple of feet in length, a bar, and electronic diversions such as a television set. He charges anywhere from $33,000 for basic budget limos to several hundred thousand dollars for armor-plated cars. With tougher drunk driving laws taking hold around the country, these are good days for livery services. Moloney says that sales should grow 50% to $25 million this year. His company recently moved into a factory once owned by Bally Manufacturing Corp., a firm his family started during the Depression.