How are you guys doing overhead paging on an IPedge? I am thinking IPT, BESCB1A, and HESC1A-65 cable. This would all hook into a paging amplifier. I also thought of one of the various SIP paging interfaces but you cannot add a SIP device into a paging group so there is limitations there.

I installed the same thing for a customer. We tested some other SIP options, such as a SIP paging horn, but as you mentioned you can't add a SIP device to a paging group. You can only make a direct call to the paging extension.

This is the best option when you need to use a paging group, but I don't like how many devices are required for paging. At one location I have the phone mounted to the backboard with all the paging equipment. I also disabled dialing (I moved the Intercom key to a hidden button). You don't want people using that phone. The only issue I had was that 2 times the IPT phone stopped working for unknown reasons. I had to go onsite to power cycle the phone.

For SIP paging, I have heard that the SNOM PA1 works good.
In the lab I have tried the the Valcom VIP-801A and the Axis C3003-E SIP paging horn speaker.