Two questions about xsi:type

[KevinBenson]

As I am modifying the RI doc, I noticed two questions that we did not 
quite discuss or resolve unless I was out of the room :)

1.) As noted XPath will no longer need prefixes hence vr:title will now 
be title because of the schemas being elementformdefault="unqualified".  
Should @xsi:type be an exception? (Currently as I work on my laptop I am 
placing it as an exception, so is that correct?)  I am not certain yet 
if any of our schemas define an attribute named "type"  As you can see 
though "type" attribute in the nonamespace is different from an 
"xsi:type" attribute.

2.) If I wanted all the SimpleImageAccess Types I would have some kind 
of query that would normally do  "where @xsi:type = 
'sia:SimpleImageAccess'".  How are we to handle the prefix piece on the 
@xsi:type?, obviously you can do a "where @xsi:type like 
'%SimpleImageAccess" hence query via substring, but probably not the 
best solution, but would work for everybody. 
Or can we say there is a predefined prefix such as sia, vs, cs?  (this 
might be the most ideal solution since we tend to always use the same 
prefixes even on extensions we seem to always use the same such as ssa: 
or cea:)
As you might be able to see a relational db could sort of handle it 
better because most likely a table is named SimpleImageAccess and they 
can just strip the "sia:" prefix piece to query the table,  but current 
looks of an xmldb might not be as easy seems to treat the xsi:type like 
a regular string.

cheers,
Kevin