A macro containing a mini-macro?

[HiPhish]

Hello Schemers,

I have written a small macro for writing test specifications:

    (define-syntax test-cases
      (syntax-rules ()
        ((_ title
           (given (byte byte* ...))
           ...)
         (begin
           (test-begin title)
           (call-with-values (λ () (open-bytevector-output-port))
             (λ (out get-bv)
               (pack given out)
               (let ((received (get-bv))
                     (expected (u8-list->bytevector '(byte byte* ...))))
                 (test-assert (bytevector=? received expected)))))
           ...
           (test-end title)))))

The idea is that I can specify a series of test cases where each case consists 
of an object and a sequence of bytes which this object is to be serialized to:

    (test-cases "Single precision floating point numbers"
      (+3.1415927410125732 (#xCA #b01000000 #b01001001 #b00001111 #b11011011))
      (-3.1415927410125732 (#xCA #b11000000 #b01001001 #b00001111 
#b11011011)))

This works fine, but sometimes there is a sequence of the same bytes and it 
would be more readable if I could write something like this:

    ((make-vector 16 0) (#xDC (16 #x00)))

instead of writing out 16 times `#x00`. This would require being able to make 
a distinction in the pattern whether `byte` is of the pattern

    byte

or

    (count byte)

and if it's the latter construct a list of `count` `byte`s (via `(make-list 
count byte)` for example) and splice it in. This distinction needs to be made 
for each byte specification because I want to mix actual bytes and these "RLE-
encoded" byte specifications.

So I guess what I'm looking for is to have a `syntax-rules` inside a `syntax-
rules` in a way. Can this be done?