>     (bytevector 1 2 3) is a standard procedure in R6RS and R7RS. Is John
>     planning a convenience procedure with the same name that is more
>     lenient
>     about the types of arguments it can handle?
>
> Just so, with some other helpful procedures.  The almost-SRFI is at
> <http://htmlpreview.github.io/?https://github.com/johnwcowan/r7rs-work/blob/master/srfi-2xx.html>
> and Wolfgang's implementation is at
> <https://github.com/Zipheir/bytestrings>.

Your procedure is named `bytestring` so you are keeping the semantics of
the RnRS `bytevector` procedure intact. That's good. `bytestring` is a
welcome addition to the language. The spec seems exactly right to me.

(Tangentially related: I have a "Symbols as strings" pre-SRFI that has a
similar procedure to make a symbol by concatenating assorted things.)