On a smaller cat like that a couple quality 4 stroke
outboards could be pretty nice. They make some 8hp and a little larger high thrust versions (12" prop!), that are pretty nice with power tilt etc. Having said that, a diesel
is hard to beat, especially if you need to power a big alternator
etc. I would want two diesels rather than one of the wierd mid boat setups a few sold. You could consider a TPI built Lagoon 37
if you can go a little bigger than your 34. Great boats and dual diesels. OTOH, if you get a smaller boat and it needs engines, two new 4 stroke
kickers wont cost and arm and a leg.... add a Honda
2000i and some solar panels
and you are READY!