[plt-scheme] literal objects in code?

Is it possible to insert literal objects like hash-tables into
macroexpansions in mzscheme?  I know this is generally forbidden
in Scheme, but I wonder if you guys have defined some switch
that allows it.  There are lots of things you can do if you can
do this, e.g. define a constant time case expression on integers
by inserting an array built at macroexpansion-time into the 
code.  --pg