If you prefer a physical book, several editions include the Roman transliteration feature: IslamHouse.in : Offers a Kannada-Roman Qur'an that includes Kannada, Arabic, and Urdu scripts. Deen Store : Carries the Al-Quran'ul Kareem Complete Translation In Kannada : Lists the Abdussalam Puthige translation
The closest alternatives are:
: A popular edition available through Islamhouse.in that includes Arabic, Kannada script, and Roman Kannada transliteration. Kannada-Roman Qur'an roman kannada quran pdf