Tom, two add'l thoughts for you:
-- You have to commit to a genuine dedicated search before you can conclude that any given type/brand/model isn't going to be acceptable to you and/or your wife. For the sake of discussing this a bit, I just grabbed the first Grumman Tiger listing that popped up in Barnstormers to illustrate:
http://www.barnstormers.com/cat.php?mode=search I really don't mean to 'push' a Tiger exclusively tho' it does come close to matching your long-term goals. My point is that you need to investigate the brand & model in depth before either of you can conclude it 'won't work' or 'isn't modern enough'. E.g. this listing has just been worked over by Fletchair, which means people who know Grummans intimately have done the work, have (or have access to) all the new/refurb'd parts needed, and who can provide whatever transition training you would need. (FYI the owners' association -
http://www.aya.org/index.php - operates a Pilot Familiarization Program all around the country). Does it look new enough? Well, what does 'looking new' get you? Is it clean, do its logs reflect the right kind of (qualified) care it should have received? If some aspect of it lacks sufficient 'newness' (typically, this means the paint, the interior, the panel or the windshield glass), what's the cost of improving that aspect?
Moreover, one of the key concerns most spouses have about any airplane choice is safety. 'Will it be safe to fly? Would I want my kids flown in it?' Accident stats for the AA-5X series are quite good by comparison with other simple Part 23 a/c (see e.g. the Aviation Consumer reviews). No one likes to think about their plane facing an off-airport 'landing', but the reality is that survivability of the airframe plays a big role in passenger survivability. You only have to see a few pics of conventional 'aluminum skin on aluminum frame' a/c (Cessna, Piper, metal LSA's, etc.) after a crash to understand how poorly that construction method performs in even controlled off-airport landings in rough terrain. Basically, the airframe is shredded apart. The kind of monocoque composite construction used in LSA's is no better, perhaps worse. A Grumman's honeycomb/composite/aluminum skin structure is quite different with the portion of the airframe surrounding the cockpit far safer in that sense. As are it's wing spars. There has not yet been a recorded in-flight spar failure of a AA-5X Grumman. My point is that it takes some time to peel the onion and fully appreciate ALL of the factors that make an a/c safe...or at a more general level, 'acceptable' or even desirable. Including your wife in this process is perhaps the single best way to insure that she'll end up being a full partner in your flying. It requires her to invest her time in something that might not initially interest her, but it surely will increase her comfort as well as her enjoyment in whatever you end up buying and making a part of your lifestyle.
-- In my limited experience, Eddie and his beautiful spouse are more the exception than the rule. Tandem seating, as he mentions, is the less popular choice (a relevant fact when you must later think of resale), but beyond that most tandem seat configurations are flown by guys who are absent their spouses/partners. There would be even fewer tanden seat airframes if it only couples were buying them. (E.g. I know lots of folks in the RAF who fly tandem a/c like RV's and Husky's. Only one routinely enjoys his wife's company). Especially when the other person is not a pilot, it is interesting and educational for the passenger to be seated next to the pilot and able to observe all that's going on, rather than buried behind him/her. Side by side seating has many other benefits, from having a helper when one is needed (fetch the sandwich) to better enabling some Pinch Hitter training, to the full sense of inclusion in the experience. None of the above, of course, is as important to you as your statement "My wife wants side by side seating..."
On another note, I apologize to the group...as Paul is correct. I obviously got hyperventilated when combining thoughts of cost effectiveness with flying. I'll try to be more practical in the future. <g>