In patients like yourself, a more traditional tummy tuck carries a significant risk of taking you from your current appearance (trim but with perhaps a bit more abdominal roundness than you would like) to looking funny or strange. Your abdomen would be flat, yes, but it may not be an attractive change, because you would have undergone a procedure designed for people with more skin than you have. I don't think trying to force a square peg into a round hole is the best approach.
At the same time, liposuction alone is not likely to give you the flat, athletic appearance it sounds like you are desiring.
In cases like yours, the option that has worked best for me and my patients has been a Modified (or Hybrid) Abdominoplasty, in which a smaller incision is used to allow access to the entire musculature (so much more improvement than a mini-tummy tuck).
This is a relatively sophisticated technique that does require special equipment and experience- so there are some surgeons out there not even aware that it is possible.
Find a surgeon certified by The American Board of Plastic Surgeons with a lot of experience in abdominal contouring that you like and feel you can work with. Ask to see photos of other patients who have undergone the same procedure, and maybe even to talk to a few.
I think what you want is possible, but its important not to end up regretting your decisions because options were limited. Your situation requires a special technique for the best outcome.