Good Signature Drink
I'm not a fan of sweet vodka cocktails, but regardless I would recommend something less strong before a mid-day meal, some kind of highball or punch. Punches in particular are enjoying a new vogue right now, and it's easy to find lots of interesting recipes online, like sangrias. They're easy to serve, too: mix once, let guests dish up their own.
Some ideas for other tall but not too strong drinks:
Champagne cocktails and sparkler/juice combinations like Mimosas (fresh OJ makes all the difference) and Nantucket Reds (with cranberry juice cocktail)
50s/60s retro highballs like the classic whiskey/ginger ale highball or Tom Collins.
The Americano highball, a mix of Campari, sweet vermouth, and soda.
Fresh lemonade mixed with vodka, rum, or whiskey (bourbon works nicely).
Ginger-beer cocktails like the Moscow Mule and Dark and Stormy.
Gin, vodka, or light rum and tonic with fresh lime
La Paloma: tequila and grapefruit soda (Squirt is traditional) with lime (optional: a bit of salt), kind of the highball equivalent of a Margarita
Mojitos, though these are labor-intensive and kind of tired
In cold weather, hot mulled-wine punches like Swedish glögg
Fill white wine glass with ice
Fill a shaker with ice and add 1.5 oz vodka, 2.0 oz white grape juice, .5 oz fresh lemon juice, .5 oz simple syrup (easy to make , just boil 1 cup sugar and 1 cup water until sugar dissolves and chill afterwards). Shake and strain over ice in glass. Add a splash or so of club soda and .5 oz of Chambord or Creme de Cassis. Garnish with a couple grapes or berries. Call it whatever you want that seems appropriate.
Since the mods yanked my original reply here, I suppose I need to edit it.
OP, Tony's drink sounds like a pleasant lunch drink. I suggest using a collins-type glass in lieu of the wine glass, though: it'll look much more professional.
I agree with c_oliver: rose is a great idea.