So my mom wants a Miata...

[SlimKlim]

HOLD UP. I wonder if I could convince her into an S2000 hock:

I wouldn't. Inevitably she'd take it out on a slushy day or just hit some sand/gravel in the road, and then come home and skin you alive for selling her into a car with no traction control.

Also, looks and reliability aside, the older TTs just aren't that nice to drive, far too heavy footed and sluggish for how small and impractical it is. If you want to go for something more premium, get her into a Z4. They've come down to $14-17k and while they look goofy, and probably aren't great track cars, are actually really fun to drive. The long hood and low slung driving position make it feel like an old school roadster, the 3.0i designation is pretty respectable and the 3.0si has bawls.

I'll throw my vote in with the NC as well. Comfortable, modern creature comforts, Mazda reliability and cost of ownership, and still a great car to drive. While its no NA in terms of go-karting around a corner, they really managed to capture the charm of the original miata in the drivetrain. Peppy, nice sounding little 4-banger and clicky, fun to drive transmission. They also have an auto with paddle shifter thingies if she didn't want to work a clutch pedal.

EDIT: Does the NC have pop up roll over bars? I know the Z4 does, it seems like that should be a requirement on modern convertibles.