I believe you can use the TB7300 as AS-IP voters if you need something in 1RU, but the most cost-effective option is probably a TB9400 with just the reciter and PMU. You can put multiple reciters into a single subrack if you have multiple channels per site, so you can actually beat the density of the 1RU TB7300, and not pay for a PA. All of this will be dependent on your network being a Tait AS-IP network.
I'd recommend reaching out to a Tait dealer to quote/build this. Tait supports a good variety of configurations and custom solutions on a per-customer basis that their website and brochures don't fully cover, but a good dealer will be able to work with you on it.