Well we're pretty sure you've made up your mind to do this, but in all reality, you need to pick one person who you trust and not seek advice from online forums, in my opinion.
In certain circumstances, HUD and bank owned homes will make you sign forms which state you intend on using the home as your primary residence. If you sign that form and then "flip" the house, you're going to find yourself in a lot of trouble for making a purchase under false pretense, as many banks have investor only bids after owner occupants.
Like many have said, there is no such thing as a short sale expert. Each bank, each seller, each situation and circumstance are different and cannot be generalized. One bank and loan could take 2 weeks, whereas I had one last week close after 9 months and 21 days.
You also need to define "worthwhile" as what may be so to you may not be to another.
As I have said before, set your sights low -- buy something solid, which needs low out of pocket expenses and try to sell that for a MODEST profit.
Any investor (especially on their first try) has MANY things to learn and more often that not, they're painful experiences. I'd advise take whatever amount you think it will cost and DOUBLE it. Then, take any profit you thought and REDUCE it by half.
If you can stomach what is left after this, then welcome to the world of investing.