(Edit: My comment here is regarding the device pictured in wcreed’s comment.)
This is something I have looked into recently.
I love using the number pad for my durations and it would also be helpful to have the arrow keys right there as well!
(As a bonus, it has all those other keys, too, including PgUp/Dn Home/End and some extra F Keys!)
However! I looked around online a lot and the only versions of this device I could find were all Bluetooth* and some had reviews of double inputting or needing to double-press for one input—overall latency issues. Just something to consider, though I really enjoy the idea of using one of these in conjunction with a midi controller!
*There was one made by and for Apple, as well, but I don’t have an Apple computer so don’t remember if it was Bluetooth or wired.