[racket] keyword arguments for type constructors?

Is there a way to define a type constructor that accepts keyword arguments?  

I know that things like the Class type constructor do this already, so is there a way to define something like this myself?  

The reason is I have a struct that represents a dimension (as in dimensional analysis and units) and I want a type constructor that lets me make types for specific instances of it without having to remember what order the fields go in:

(struct: (Length-Expt Mass-Expt Time-Expt Charge-Expt Temp-Expt)
  dimension
  ([length-expt : Length-Expt]
   [mass-expt : Mass-Expt]
   [time-expt : Time-Expt]
   [charge-expt : Charge-Expt]
   [temperature-expt : Temp-Expt])
  )

(define (dimension--kws #:length^ [length-expt 0]
                        #:mass^ [mass-expt 0]
                        #:time^ [time-expt 0]
                        #:charge^ [charge-expt 0]
                        #:temperature^ [temp-expt 0])
  (dimension length-expt mass-expt time-expt charge-expt temp-expt))

;; I want to be able to do something that would do the same thing as this: (it doesn't have to be this easy)
(define-type (Dimmension--kws #:length^ Length-Expt
                              #:mass^ Mass-Expt
                              #:time^ Time-Expt
                              #:charge^ Charge-Expt
                              #:temperature^ Temp-Expt)
  (dimension Length-Expt Mass-Expt Time-Expt Charge-Expt Temp-Expt))


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