I wanted this functionality myself so I took a half hour and cobbled together some dirty code myself. The code below will match entries from CapsMan then display the following:
Host Name, CapsMan Interface, IP Address, IP Address Expiry Time and the Mac Address of the Client.
[:foreach i in=[/caps-man registration-table find] do={([:local M [/caps-man registration-table get $i mac-address]]\
.[:put [/ip dhcp-server lease get [find where mac-address=$M] host-name]].\
[:put [/caps-man registration-table get $i interface]].\
[:put [/ip dhcp-server lease get [find where mac-address=$M] address]].\
[:put [/ip dhcp-server lease get [find where mac-address=$M] expires-after]].[:put $M].[:put ""])}]
Feel free to criticise (please do criticise it because I find my main weakness is in understanding syntax and I'd love to fix that) and or improve it. I'm sure it can be added to and condensed a lot,
however I'm not a very good at coding so this is what I can provide atm.