In order for you to install the call pilot VM, you will need to replace your current phone system in order to be compatible like mentioned above in the prior post (CICS/MICS 4.1 Minimum required to work with call pilot).
I don't think that you can get a phone system and call pilot VM with the bells and whistles (Unified messaging that entire advanced feature like you mentioned) and installed for under or even $2000.
In regards to the flash VM it will not provide you with the features that you required.
That’s my opinion