I think you will need to pay more money for a decent sounding wooden guitar than you will for a resonator. The quality of the wood and more demanding construction (for tone and volume) means the cheap far eastern ones usually sound quiet and lack sparkle. Which is why I tend to dislike them. Of resonators - dobro copies (spider bridge) tend to have more problems than the national (biscuit) type, but a decent replacement cone works wonders. I have a cheap far eastern Regal (look at the avatar) and did some work similar to Peter's on it. Bone raised nut (an old one robbed off a dog; really, they get seasoned that way), quarterman cone and ebony bridge saddles (from a wrecked violin fingerboard). The big secret is setting up the spider assembly (seating the cone, NO GLUE, and getting the tension just right can be tricky), which is why the biscuit type are easier, simply bang in a better cone with those and you're generally fine.
Tony.
As an afterthought in line with your last idea: a couple of years ago found a cheap roundhole/flat-top with tailpiece, there were loads of them sold in the 50/60's. It was slightly better than most and £5
with case! Just had to raise the nut and it works well enough. It'll be better shortly when I stick an old Hofner p/up on it - a proper Bob Dunn jobby!