Here is two English-Ukrainian Kobo dictionaries.
Source dictionaries I took from
here,
and I have converted to Kobo format using
Penelope.
dicthtml-en-ua.zip
English-Ukrainian dictionary
Words count: 63,287
Qualitatively decorated, looks good in Kobo.
dicthtml-en-ua-2.zip
slovnyk_en-uk
Words count: 138,169
In terms of the number of words, this should be larger, but in terms of quality of design, it is worse.