I think her chances of winning are pretty remote as I don't think she has the stamina to stay at the top of her game for two weeks, something she has admitted herself, but since you are looking at trading that might be what you are thinking too, as she could negotiate another few rounds.
Looking at the draw, and it looks fairly kind to her. Assuming she takes care of Emma Laine, it'll most likely be Mary Pierce after that.
The Aussie open was Hingis' most successful tournament in her prime, with a fairly awesome 44-5 record over the years, while Pierce has gone out by the 2nd round in her last three tournaments here. Hingis leads 8-2 on hardcourts, although its pretty clear these shouldnt be given too much importance as that was a while ago.
Two of those were in melbourne with straight sets Hingis wins both times. Hingis was though easily beaten by Henin in Sydney, and could find herself up against it versus Pierce, who finished 2005 reaching 4 finals out of 5.
However, having not played prior to Melbourne this year, and at one of her weakest Slams, maybe Hingis has found one of the most vulnerable high seeds here, and has a fighting chance, and if she comes through v Laine quickly she should still be fresh enough to give Pierce a good game.
If Hingis were to get through v Pierce, the draw could open up a little - with Clijsters very vulnerable to injury in her quarter.
So back to the question - I think it all depends on how the market moves. There's a chance that given fitness concerns the odds on Hingis winning wouldn't move much even if she managed to beat someone like Pierce, so as always its a case of weighing up the pros and cons of backing her in her matches, or trading on the outrights.
Hmmm, so thats not really reaching a conclusion
If anything I might have left the outrights until after her next match - Laine beat Vives 6-1 6-1 in the first round, while it took Hingis 3 sets to beat the same opponent a few weeks ago, and given the odds of just 1.13 and thereabouts on Hingis for this one the outright odds won't move much even if she wins.