In my experience, this time with sour cherries, I found that juice concentrate works better than real fruit. 10lbs of tart cherries (which was expensive, from the grocery store!) gave a slight color and not a whole lot of flavor to a 5 gallon batch of mead. I was quite disappointed. But a dose of sour cherry juice concentrate had a marked effect!
My only qualm with extracts is that sometimes they add aroma but not much flavor. Had that problem with apricot extract in a beer, and I've noted it in commercial beers using extract. They kind of smell distinct in whatever fruit flavor they have, but there's no flavor, just a kind of disembodied aroma. It seems all of my best fruit flavored meads and ciders and beers have used juice (in the case of extremely strong juices like blackcurrant) or juice concentrates. But my experience isn't broad enough to call that anything beyond coincidence, and I'm not aware of a good raspberry juice for that purpose.
Good luck with the beer though, hope the wife likes it! Liqueur sounds like a good idea. I'd probably skirt the highest end stuff (such as German himbeergeist, etc), you really want something with a lot of raspberry flavor, not a subtle liqueur made for appreciating on its own.