If you're going to do an engine swap you need to consider your skill level. If you have no idea what you're doing pick an engine that is commonly swapped so that there's a ton of information out there on it already. If you do have knowledge then just pick whatever you want and say 🤬 the haters.
Remember there is no such thing as a "sacrilegious" engine swap. The only people that are concerned with that crap are bleeding hearted fanboys and ignorant rednecks ("Y'all ain't gunna be puttin no Toy-ore-ter motor in dem Key-marrows). Most of the people who'd hate on your engine swap are probably just jealous that either a.) they don't know how to do it or b.) you came up with a better idea.
I assume if you're talking about flappy paddle transmissions, you're planning on dumping some money into this project since there is nothing cheap about doing that kind of trans. So dream big and see what you can come up with.
I'd say look at a 2.0L EcoBoost engine but I don't know if Ford is selling those yet as crate motors. Another alternative would be an SRT-4 swap. A buddy of mine is in the process of building a the 2.4L Chrysler Long Block that is twincharged (you know both super and turbo charged). It currently is only running the supercharger and puts down around 300hp to the wheels. It's in a Dodge Neon right now as sort of a test mule, but I think the ultimate goal is to dump it into something completely unique. I know he's said maybe a shortbed Ram or a Subaru WRX.
If it were me building something like that, with a half way decent budget I'd shoot for small and forced induction over a big V8. It'd be way more unique and if you did your research it could be much lighter too.
Or you know, you could just put an LS1 in it because LS1's fit anything