To answer  this I need to clarify several things.

1. There is no hard coded or recommended limit  to the number  of Web
Applications you can have in SharePoint. There is a soft limit on the number of
Application Pools that you can run on an IIS server. Since each Application
pool requires memory  for the web  site plus about 100Mb of overhead the amount of
RAM in your server will limit how many app  pools you can maintain. Microsoft's
recommendation for a 32 bit server is no more than 5-7 app pools. Since each
Web application  can run in its own app pool many people talk as though there
were a limit on the number of Web applications  you can run. If you are sharing
App pools or have sufficient RAM in a 64 bit server then this limit does not
apply to your situation. (Of course running 50+ app pools on even a 64 bit
server is not something I would recommend.)

2. Although each Web Application starts with one content database you can
always add more. Having two site  collections on the same Web App doesn't mean
they have to be in the same content database.

3. Although there is no hard coded limit on the number of Web Applications
you can support, there may be a realistic limit based on your hardware. Each Web
Application is a separate Web site as far as IIS is concerned. Since all Web
Applications will be created on all the sharepoint  web front ends you will need
to test your WFEs to make sure they can handle 50+ web sites  in IIS. Although
there isn't a hard coded limit in IIS, your hardware may not be able to support
this number of web sites.

So unfortunately, no one can give you a definitive answer because there isn't
one. It depends on your hardware and your design. It is possible to create  a
SharePoint design with 50+ Web Applications if they are sharing Application
pools and running on 64 bit hardware. Whether you can get enough hardware to
provide adequate performance for that design is the question. it's not the way
I would normally recommend designing it. I would suggest something in between.
Does your university actually contain 50+ colleges? Or is there a different way
to design the web application/site collection  boundary. For example, have
colleges be a Web Application with site collections  for each School. I counted
16 colleges on UFL's web site. That would be a more manageable number.

Check out the web site below for the Microsoft recommended sizing limits for
SharePoint.

technet.microsoft.com/en-us/library/cc262787.aspx

Also, for general information [I should have included this in my original post.
Sorry.], my hardware is (5) server farm of (2)WFE, (1) index and (2)SQL cluster
A/P. Hardware is all 64 bit DELL Intel(r) Xeon(r) X5560 with 24Gigs/(6x4GB),
1333MHz of RAM.

You can have more than one site  collection per web  app. You can backup and
restore site collections  independently via stsadm (you don't need separate
DB's for that purpose).