Q:

Ready as I'll ever be

Yesterday I was helping a student translate a story she'd written from English to French.
It contained this exchange between two people on surfboards about to ride a terrifyingly big wave:

— You ready?
   — Ready as I'll ever be.

The answer given is a stock expression (the subject can change but nothing else).
It's easy enough to give a literal translation; one might say:

Aussi prêt que jamais je le serai.

However, I don't think this captures the tone or all the meaning of the idiomatic English phrase.

Je ne suis pas vraiment prêt, mais je crois que ne le deviendrai pas en restant dans l'attente. Je sais que tôt ou tard il faudra agir et au moins je suis suffisament prêt pour surmonter ma crainte.

Is there an equivalent stock expression in French? Or can the literal translation convey all that?

A:

It's possible to use plus prêt que jamais which as an answer would often be shortened as follows:

— Tu es prêt ?
  — Plus que jamais !

Another very common phrase is “C'est maintenant ou jamais !”.

A:

I would use this idiomatic expression but it might be a bit too formal/literary:

— Autant que faire se peut !

To keep in the colloquial tone used in the English dialog, that might be simplified to:

— Autant que je peux !
— Je peux pas être plus !

or, as suggested by Tensibai:

— Autant que possible !

A:

A more litteral translation would be 

Je n'ai jamais été aussi prêt

