Have done exactly that using GOOPS which is Guile's equivalent of CLOS:

  scheme@(guile-user)> (use-modules (aiscm sequence) (aiscm element))
  scheme@(guile-user)> (define a (arr (1 2 3) (4 5 6)))
  scheme@(guile-user)> (get a)
  $1 = #<sequence<sequence<int<8,unsigned>>>>:
  ((1 2 3)
   (4 5 6))
  scheme@(guile-user)> (get a 1)
  $2 = #<sequence<int<8,unsigned>>>:
  (4 5 6)
  scheme@(guile-user)> (get a 0 1)
  $3 = 4
  scheme@(guile-user)> (get (get a 1) 0)
  $4 = 4

That's the whole point of macros: To be able to create embedded domain specific (mini) languages.

[1]: https://github.com/wedesoft/aiscm