Storm Lake makes a general production "one size fits most" barrel, and a special production true "gunsmith fit" barrel. I asked Questar about special ordering for me, but basically got a canned reply that told me they had no clue the special order barrels existed. As far as slide to frame fit goes, it should be possible to add weld to the ears of the locking block and sear block and then re-cut them to reduce slop in the slide/frame interface. I asked Randy Lee (Apex) the same question some time ago and he agreed that it would improve the repeatability, which would (should) always result in increased accuracy. Another consideration is the timing - Smith has re-engineered the guns to control the timing, and change the barrel to improve performance with heavier bullets, doubtless there's more that could be done with regard to the upward tension on the barrel hood. The problem with both increasing the frame rails and increasing the tension upward on the barrel, is that the parts that provide these 'services' are MIM parts, made of not publicly known alloys, so getting the right wire to add material is somewhat problematic.