Hmm. Probably best bets for decent luxury with more reliability and cheaper maintenance :
G35 Sedan, they can be found with good condition for that price..
or
4G Acura TL, also can be found around that price range. Great interior, fantastic sound system and overall fit/finish. This was the TL *after* the infamous Honda auto tranny failures. My brother's wife has one with ~150k miles and only routine maintenance.
Outliers : BMW 5-series (similar maintenance cost to Mercedes though), M35 (not very common), Legacy GT (probably not enough lux for you)