CSR-based bluetooth > uart dongles are like $10/ea and have zero problems reliably transmitting at 115200 baud (within reasonable distance, of course).
Not sure what the problem with Flora BT module is, have you actually tried setting baudrate on it higher?
Also character loss could be anything from the transmitter end not properly sending to receiver dropping them, so I wouldn't be 100% sure the problem is due to one end or another without more information.
Anyway, I'm not sure why the budget is so high, you just want a breakout module to replace flora BT, right? In that case its like a $10 thing.
however if you're asking to develop a new PCB which contains these parts, then the bid will be higher. please clarify.