What are the issues you're having with your Zodiac sib?
The Zodiac Pro 420 and 500 (used to be called 7-man and 9-man Pro) both suffer from 'hull slap' because they have relatively shallow v hulls. I used to have the 420 and it was fine in calm waters, but an absolute pain if the wind picked up. Another thing is load, and the number of people on board, as this all helps if you're running against wind and tide. I also had a Zodiac MKIIC Grand Tourism sib, and it was out in all weathers, but needed my brother up front for ballast!
Not sure what boat makes you have access to in Canada? But something up to 5m, decent deep v hull, hypalon tubes and outboard power up to 70hp would certainly fit the bill. This could include Avon Searider 4.7m, Ribcraft 4.8m, Ribquest 4.8m, etc. What's your used market like?
Is that with or without VAT?