Did you have a hand in this?

[ReNardier]

the proposal for more legacy computing characters in unicode
http://www.unicode.org/alloc/Pipeline.html
http://www.unicode.org/L2/L2021/21235r-terminals-supplement-noattach.pdf
if unscii has some characters that they didn't propose, you could get in contact with the proposal creators to see if they'd be willing to draft a small one for those characters
i personally would have contacted them for the CH and ch from http://www.cestina.cz/kodovani/dvojznaky.html#KOI8CS but it seems a bit silly to bother them for just two characters of an obscure czech encoding, have a good day

[ReNardier]

id also recommend you make a version of your fonts that doesn't or
barely uses the PUA(if whats been proposed for inclusion in
unicode proper allows for it, i think that "Bob", the pac-man ghosts
and a few others will still need to be PUA), that way people can use
unscii and for example an ucsur compliant tengwar font, or their
specialized PUA font if they need