Yea, the inline diesel would be an eye sore sticking out of the hood. My friend thought of that (he has had cummins for about 10 years). He figured that if you were going to put that engine in, then it would not be for street use....or at least a very loud DD with a massive hood scoop or cowl hood.
As much as I would hate to say it....the best thing to do is maybe make some contacts over in Europe and start saving your money for a used boxer diesel. but again, with the diesel over their making 253tq at 1800rpm....get ready for some power.
Personaly I can not wait for the diesel to come out in america. I show my buddy (diesel maniac) the stats on it and he had a rather big smile. He said that with his help, that he could get an extra 100hp and 100tq out of that little boxer. Just give him a month with the engine and he can do it.
But I say go for the TDI conversion. at least there are plenty of parts and forums out there to help you along the way. And who knows.
Personaly I will be waiting for the boxer diesel.
GL!