You are correct, the 3.5 was never a cloud car option, but it was brought up, so I went with it because it is based on the narrow angle 3.3 which could be had in transverse FWD. The 3.5 is MUCH wider however because of the heads. That's the main reason I think we've not seen that swap in our TD's. The other glaring issue is there is no 5-speed option.
The thing is (and I could be completely wrong here as I honeslty don't remember) that I thought the 3.3 and the 2.7 shared bellhousing patterns. Because of this it solves (sort of) the lack of a manual transmission for that engine series and makes a 3.5 transverse swap a bit more of a realistic dream.
Anyway, back on topic. The 2.7 *can* be a decent runner if taken care of correctly (most weren't and aren't). This ONLY applies when they are left in mostly stock configuration. They absolutely do NOT have the internals for boost or squeeze. To my knowledge there is even LESS support for the 2.7 than there is for the 3.0 (which is hard to believe!). Building one to make power reliably is going to be an expensive proposition, and probably ultimately futile. Notice I'm not saying it CAN'T be done, just that it really doesn't make much sense to.
I will say this, if you build a screamer 2.7, it will be VERY unique indeed....