Hi abf
I work for a global leading business school in Lausanne in their MBA team and amounst other things, handle financial aid. Unfortunately I can confirm that it is almost impossible to get a student loan from a bank in Switzerland - we have negotiated with 2 of the leading banks and have come to a agreement but unfortunately only for us.
I would suggest that you contact SallieMae again and be sure to ask for a "Private Signature Loan" for these, the school does NOT need to be on the list for FAFSA/TitleIV/Dept of Education - we aren't and our participants are eligible - I did jump through hoops for Sallie Mae to convince them but someone at St Gallen should be willing to do the same.
Below are a few other links you can try.
www.gradloans.com www.finaid.org www.internationalstudents.com www.topmba.com/scholarships
If I can help further, PM me and we can have a chat if you like.
Good luck
Nats