The EV1527 / PT2272 etc. are intended for "dumb" remote systems where a CPU is not needed.
If you are using microcontrollers anyway, you can do it entirely in software, and pass as many data bits as you like!
A system we build uses an eight-bit address for each device, set using a couple of hex DIP switches.
The transmitter & receiver use PICs, with the serial port pins connected directly to RF module data in & data out (at the TX and RX respectively). Depending on the radio modules the serial data speed could be anything from 9600 Baud to 38400 or more.
Everything else is just software..
Turn the TX on, send a few 0x0F characters to allow the receiver to settle, then send a unique character or two that are recognised as "this system" ID, then the address and data bytes.
Each address or data byte is sent twice, once normal and once inverted. That allows for error checking in the receiver, by checking the repeat of each byte is it's inverse. You could add a CRC to the overall data frame as well.
Plus each transmission burst is repeated a couple of times at short random intervals, in case anything else was transmitting at the same time.