Q1: Can attachements be viewed via Service Pages? Out of Box the answer is no. SP can be modified but yo uhave to code it yourself. Some previous posts should have details on this.
Q2: Can attachments be view through the approval page? Again, Out of Box for SP the answer is no.
Q3: How many 65K text fields can I have on a form? Only one as by default OVSD only gove you one f these fields. SP 18 has the functionality of unlimited fields but I dont think this extends to additional 64k text fields.
You could develop a small web app to hold the documents, then link them to a Service Desk record (using the Service Desk record ID in the web app as a way to 'group' the documents). Then develop a Service Desk Change Request Action to open the web app & related docs by passing the URL & Service Desk record ID.
As previously said regarding Q1&Q2: the out-of-the-box functionality for ServicapAges does not provide access to attachments. However it can be added (we have done that several times).
For Q3 the answers you received is true as well.
What I have suggested few times here is to make replacement for lib_ftp.jar that woudl support different methods of attachments storing (like SFTP, FTPS, database, ...). We are able to make this if there's enough interest (that means you have enough funding ;-)