650c wheels bicycle (for 5'3 and under)

im a newbie to bikes in general, need HELP! :-S im quite short (5'3) and finding it hard to find a small track bike under 50cm. 50cm bikes with 700cc wheels are uncomfortably high (tip-toeing when seated), is it possible to swap the wheels 650cc to make it smaller?

No, the seat stays will be too long to fit a smaller wheel on the back and you'd need different forks on the front.

How about the Fuji Track SE? 650c wheels on that. I have one and use it to ride around town (it's got brake holes drilled) but I'm sure it would be fine on the track.
http://www.velodromeshop.org.uk/index.php?p=product&id=217

Islabikes also has a small track bike these days, http://www.islabikes.co.uk/bike_pages/reis.html

Why are you concerned about being tiptoe when seated though? I'm shorter than you and do fine on 700c wheels (though I prefer 650c for racing). If you have your feet flat on the ground while seated on the bike, that would mean your saddle is too low...