Sounds like you just need the saddle slightly more to the back (and also lower to compensate) until you're stable on the bike. My legs aren't very long either, I can lose or achieve stability over the front wheel by sliding the saddle forward or back on a slightly setback post, if I moved to a straight seatpost, I'd probably have to clamp it pretty far back. Of course a big change might require a shorter stem to compensate for increased reach.
Bikes with a longer front-center (that's a measurement from the BB to the center of the front wheel) are also helpful if you prefer / want more forward saddle position, As Htupolev mentions, TT bikes have the front wheel further in front to accomodate for a pretty forward saddle.