Which Banks tend to discount the most

[haugh8]

This is my first post although I have read quite a few of them.  My question is, I had several offers put into banks for shortsales last summer but they were all rejected.  The major reason was the BPO or appraised value was not close to the comps that I pulled off the MLS ( my dad is a broker), therefor our offers were to low.  Since then, I have managed rehabs that I find off the MLS or through assignment from other investors.  Our average profit after rehab is $20K but unfortunately I dont get to keep it all since the funding comes from my dad or other investors.  I want to get back into short sales since there is really no limit to how many you can do unlike rehabs which are limited by cash.  Now to the real questions?

1. Has anyone had success with certain banks for shortsales versus others?

2. Are there any banks to not even try to do a short sale with?  

3. I have seen some properties that are listed on the MLS that are bank owned for at least two years, has anyone had success at putting in major discounted offers on these properties and having the offers accepted?  If so, which banks?

I appreciate in advance everyone that will take the time to reply to this even though there is no monetary reward.  I have not seen many industries like this were total strangers will give free advice and help others by doing so.  Thanks,  Brian