OP simply asked if any current bike computers are capable of phone calls. The answer is no.

Everyone wants to pile on as to why we don't need it and why OP should feel bad for even asking. I probably don't need 90% of what all the various gadgets and gizmos that I own can do, that doesn't mean I don't want them or have fun with them or use them.

Anyway, beyond the "maybe someone wants to be able to make a call or text without taking their phone on the ride" aspect (which seems plenty valid to me) I can also think of accessibility issues for people with various physical limitations. I've had a couple opportunities to pilot a tandem with a blind rider and see some of the accessibility technologies he was working with--including an experimental technology in which there was a camera mounted to his glasses and he was linked to someone in a call center who would narrate the visual image for him while he was riding.

Is there enough demand for this type of thing to justify selling it? Probably not, but that doesn't mean there's not valid use scenarios for them. Plus as has been mentioned, there are plenty of smart watches and tablets that have the capability to pop in a SIM card and function independently of a phone, so I doubt it would even be that difficult.