Welcome to the forum!
The following link will assist you and lists several manufacturers and models..
wiki.radioreference.com
I recommend seriously looking at a Uniden BCD436HP
Any scanner listed as P25 FDMA (PH1) will work for the CMARC system (Unsure if/when they'll change/upgrade to TDMA PH2)
here are links to a few radios that will work for Harford Co. If hearing the FIRST System is also desirable you need a radio capable of P25 PH2 (TDMA) (Which all the following are capable of without any upgrading)
wiki.radioreference.com
wiki.radioreference.com
wiki.radioreference.com
wiki.radioreference.com
wiki.radioreference.com
More expensive.. but for many good reasons..
wiki.radioreference.com
wiki.radioreference.com
You can purchase from many reputable vendors. viewing the Scanner Master web site will provide a general idea of pricing of the individual models.. (And I have used them for many purchases)
Digital Police Scanner Radios
www.scannermaster.com
There are many members on the forum that are willing to provide programming assistance when you get to that point..