You're not being ridiculous. I've seen pictures of some outboard fishing boats that throw a very nice wake. The problem is that they are not designed to do so, so finding a non-wakeboard-specific boat that throws a good wake could be somewhat of an ordeal. You'd need to buy some sacks and pumps then take them along to test any boat you were looking at.
Just to help you narrow your search, you should look for hulls with the following features:
1. Narrow. Wider I/Os and outboards tend to make wider, rampier, and washier wakes.
2. Deep vee at the bow.
3. Shallow vee at the stern. A boat with a very steep deadrise will also tend to create rampier and/or washier wakes. Look for 20-degrees max though less is better.
Also, keep in mind that many I/Os and outboards will have the following correctable problems when you test drive them:
1. Difficulty maintaining wakeboard speed. This can be resolved with a lower-pitched prop and/or PerfectPass speed control.
2. Porpoising (where the bow oscillates up and down). This can be resolved by fitting a hydrofoil stabilizer onto the outdrive or outboard. This will also help the boat get on plane faster when the outboard/outdrive is trimmed all the way down. If you go with an outboard, be sure to get power trim.
If a boat you are testing exhibits these problems, you will have to consider that they are almost certainly correctable.
Finally, if money is not the issue, you can buy a wakeboard boat with a closed cooling system that is suitable for use in salt water. If you leave the boat in the water, you should have the bottom barrier coated and painted to avoid osmosis and marine growth, and install sacrificial anodes to prevent the corrosion of metal parts below the water line.