Also, Id like one with bent arms, so it could measure depth of gouges in materials. Most calipers Ive seen are straight.
Start a new tread when going off topic.
Only quote what's relevant for your question.
Go to your nearest tool shop and have a look.
Most Vernier calipers worth their salt measures outside (1) and inside (2) as well as depth (3).
If you want a good quality Vernier caliper, be prepared to pay more than you would for its digital equal. If you want one with an analog dial, bring even more money.
If you plan to settle with just one, a digital model is the way to go IMO. On even the cheapest, you can zero the display at any measure and then use it to measure diverging sizes - impossible with a Vernier scale and so is reading it in low light.
The only Vernier style caliper I've ever seen with curved jaws, is a very old model I inherited from a watch maker in the family two generations back.
Inherited one of these as well
(Good for up to 10mm).
Or perhaps you are thinking of these:
Which is used a lot in some art and copying
I've got a couple of those too, but never really liked them (except for lathe work), as you cannot get the measure immediately and so, cannot measure eg. a recess as you need to open it to remove it.